Great shit man! You are saving a bunch of people from having to do this experiment. I had already done all this in my head, so I look forward to the results.
You are great at presenting your experimentation ideas and reasoning behind them. Seems like a great test to me. There are some (really smart and experienced with lithium) folks on the solar panel talk forum who think charging with a pwm is fine - with some of the caveats that you considered. Looking forward to the results.
Winter solstice greetings Adam...! First, thank You for all your videos and work... googling this series for the second or third time. Very inspirational...! Started experimenting (again) with solar and batteries.If you have lamps as load, you can couple same types, 2 in series = Voltage divider. Saves on the buck load. The 12/24V setup seems logical, for small projects and lead/18650. It is a good idea, to separate 12 and 24 V systems with different plug/connectors ...just like we have a different plug for mains and rc.
I have worked with "sealed Gel Batteries" for 20+ years. If you open the top around the seam you will find that they do vent! There are little rubber cups over the small holes and a place for them to vent! When they dry out sometimes you can add water and bring them back
Hey Adam First of all I’ve got to say ; great videos ! They are a pleasure to watch, regarding your clear explanations, excellent video and sound quality, your expert level (as far as I can say), your scientific approach and last but not least your independancy !! I was hoping you could help me out a little bit on my décisions on how to assemble my litium-ion 18650 battery pack out of USED ones, which I already tested with the ZB2L3 modules. All this to run : - a 800 W Pump, peak times 3 makes 2400 W - some phone/camera/notebook chargers 200W - led lights 200W - 2 fans of 100 W : 200 W total power need of approxiately : Nominal : 1400W ; Peak : 3000W ; Respecting the adjustment of the total capacity per parallel ‘layers’, what if I used different cell quantities in parallel ? Simplified example : 1st serie 5 mAh + 5 mAh + 5 mAh + 5 mAh + 5 mAh = 25 mAh 2nd serie 6 mAh + 7 mAh + 6 mAh + 6 mAh = 25 mAh 3rd serie 8 mAh + 8 mAh + 9 mAh = 25 mAh 4th serie 12 mAh + 13 mAh = 25 mAh 5th serie 4 mAh + 4 mAh + 4 mAh + 4 mAh + 4 mAh + 5 mAh = 25 mAh 6th serie 3 mAh + 3 mAh + 3 mAh + 3 mAh + 3 mAh + 3 mAh + 3 mAh + 4 mAh = 25 mAh I figure that if I’d compose my pack like this, the cells are unevenly applied to when charging or discharging, so, as long as I make sure that I have enough of ‘m in parallel (so NOT like the 4th serie in the example), I ‘d eliminate the chance of extracting to many Amps at once out of a single few of them, resulting in overheating and or damage. Considering my needs, could I determine the size of my battery according to a maximum Amperage demand of 2C per cell? Let’s say, in a 24 V battery system,according to my needs, I’d need a maximum peak amparage capacity of 125 Amps (3000W devided by 24V). Every single one of the 6 series needs to be able to supply 125 Amps. If 2C equals 125 Amps, Then, C equals 67.5, lets round that up to 68 Amps. Considering that my first question would not be discouraged, one series could consist of 34 cells of 2000 mAh, a second layer could for example consist of 68 1000 mAh cells…, a third of 46 cells of 1500 mAH and so forth…… In total, this would come to a 24 V, 68 Ah battery pack of 1.6 kW… As it comes to solar charging, what affordable solar charger could you advise, according to my needs ? As it comes to converting to 220V AC, what affordable converter could you advise, according to my needs ? Do you recommend to reduce the ampérages by assembling a 48 V Battery ? Thanx in advance
+Adam Welch soon! just got 4 weeks left of 12 hour days then I should be back in the shed. Also my potential lead on recycled laptop batteries has gone silent.
Nice and simple solution! I have heard the capacity tester might be parasitically drawing more power from the first cell. Just something to have in the back of your head if you do see some cells drifting. EDIT: I now see you added balancing with tis device in part 3, so this turns into more of a note to others/other projects instead, and perhaps for other (similar) products.
For anyone intrested. They now do a EPsolar Viewstar VS1024BN, with voltages which can configured "custom". Haven't tested it but should allow for a 12v battery combination.
What made you give up on the CN3722 MPPT charger board? Was it the advantage of monitoring the voltage or load protection features? I suppose you would need a BMS to keep the cells from going too low.
+slash2314 I've not given up on the CN3722. It's not a fully featured charge controller though really and as you point out there is no load control and a danger of the cells discharging too much. This experiment isn't for permanent installation and I can't see me moving to lithium ion in the shed - everything I run is 12 volt and as I found out in the video lithium cells can't really replace a 12 volt system.
Adam, My PWM solar charger has "FLOAT", "DISCHARGE STOP" and "DISCHARGE RECONNECT". I have set 29V - "FLOAT", 21V - "DISCHARGE STOP". What voltage should I use for DISCHARGE RECONNECT. Thanks, I really enjoy the educational value I get out of your videos.
It will need to be set above your discharge stop voltage. It’s the voltage at which you’re happy to start draining the pack again. So loads are switched off at 21v currently and you may set you reconnect voltage to 24v for example. Thanks for the kind comments.
I'm pretty sure float charging (Trickle) will damage the cells. I know it will at 4.2V but I'm not sure if it will or not at a lower voltage. Either way this video came at just the right time as I was literally researching just this all day. The best solution I could come up with was an MPPT charge controller from Genasun. They are able to make custom voltages for you and they even have a voltage step up on one of their models (Perfect for my 14S pack), quite pricey though. Will definitely watch for the follow up video. As well as any other video pertaining to solar and li-ion.
+lonnie776 Quite a lot of MPPT chargers have the facility to change the charging parameters (and a fair few pwm too) but they all still work on the bulk, absorb, float charging cycle where as lithium need CC/CV. This is the test here really. The only other step up controller I've seen was the Minghe MPPT solar charge controller Julian Ilett reviewed a few weeks ago. Take half an hour to watch his videos on that... I found it very interesting.
Greetings from finland. I've almost ready to test my setup based on yours. I have Victron Solar Solarcontroller model 75V/15A with bluetooth, so i can monitor and change values from tablet or phone. It has greater setup area and its MPPT (Maximum Power Point Tracking) rather than PWM controller. MPPT hides the load from solarpanels, so it may boost the power output about 10-20% I've load the Victron without battery with 12V mini refrigerator which runs draws at 50-60W with 12V from solar and 72W with 240V AC. Works fine, until gray-area of the clouds emerge :). So i need a little backup from my rig. The rig is on a tandem-bike hooked trailer (800mm x 600mm x 415mm 165 liter capacity, watertight). Im planning to use that trailer as mobile power station in trips. I've already tested to load all kinds of things via Solarpanels and overall it looks good to me.
Fantastic video. This is EXACTLY what I was thinking about today for an off grid 7.5 watt (24x7) load. Except, I will double by battery capacity in parallel. I'll be using a 70W panel. I didn't want to use lead acid due to size/bulkiness. Amazing that I found this video as surprisingly, there's not much on this exact subject (charging 18650's with regular solar charge controller) Are you using the individual cell voltage monitor for safety (verifying periodically you don't have one cell that is way under voltage)? In my reading, it sounded like the more of these 18650's you have in series, it becomes more of a potential safety issue. Also, can this controller just be set to have a load 24x7? I will always have a load, just need the excess power to dump into the battery for night time. Phoenix, USA
+O Messner Thanks for the kind words. Yes the charge controller can be set to have the load on all the time. I'm keeping an eye on the cell voltages to see if they go out of balance or if any go worryingly high or low. More to come soon on this.
I can help with this - I think I may have already contacted you about my low-cost arduino PWM charge controller circuit? It's perfectly capable of charging li-ions, as charge voltage and current can both be monitored and controlled via software. Just program it for whatever chemistry battery you are using. You'll need to add a balance circuit to the battery if you want the cells to last well though.
Hello - yes you've sent me the info about your clever little charger. I intend to build one soon. This experiment is all about using an off the shelf product for something it wasn't fully intended for however - it's an experiment and there will be better ways to do it. Balancing is something I expected to need from the start - an update video to come soon.
I like that. Li-ion are much better choice then lead-acid. But shouldn't you get a 7s protection board? I mean if one of this cells is not balanced it might blow. I've seen some on ebay.
Well that is what experimentation is all about! I may well need a protection board - one of the things I hope to find out. All the cells are brand new, from the same supplier, all have a similar internal resistance - I might just get away with it!
I guess it should work but over time you might get into trouble as the batteries will get unbalanced. I seen 4S pack protection board dirt cheap on ebay. but the problem is you have to apply a constant voltage (i.e 16.8 for 4S pack) so some kind of boost/buck converter might be needed. Anyway it is very cool.
Yup, I agree. Some extra losses but I would like you to be on on the safe side. Also make sure that even protection boards are not a 100% safety warranty. This weekend I was charging some 2000mAh cells and 2 kept on charging it seems. I couldn't touch them anymore, they got extremely hot. The lii-500 charger reported 38XXmAh charge and they were at 4.18V . Took them out and the voltage dropped to 3.98V instantly. They are now outside in the shade for safety reasons. Yours might be all good and stable now but a protection board and a temp monitor controlled by arduino or so might be a better bet for the future.
+Luc Peeters Thanks for your comments Luc. I expect you will be right, but I'd like to run a little while without and see how it goes. These cells are new - from a reputable supplier and from tests I've run have a low internal resistance and their rated capacity. I think I'm in the best position to get away with this. Reclaimed cells could be more problematic - another day another test I guess.
***** over discharge is also a problem. +Luc Peeters A temperature sensor and arduino is very easy to implement but you have to control the power so this becomes a battery charger which you can buy ready made with dedicated chip.
Hi, I'm all set to start building this but have a couple more questions. Firstly, what amp version of the solar charge controller did you go for as there seems to be multiple versions. Secondly, did it automatically switch to 24v or do you have to set it in the settings as you did with the Gel battery type.
Ep ever auto knows when you connect your batteries if its 12 or 24v, but it can only do those 2, you need the other version for 24 to 48v but they are the same except the 24 to 48 can handle double the watt's of the 12 to 24 in solar input and in charge amperage, the video your watching is very outdated for charge controllers, i bought the epever an tracer 40 amp 2 years ago and its mppt with an mt50 controller thats remote mountabke for tuning and for a monitoring screen where ever you want to mount it.. they are lightyears ahead of this old version and i am needing to upgrade it now, so i suggest just buying a new version of either epever victron or renogy branded one because they are all the same price range and the cheapest quality ones , they come in lithium version now, so they can be fully tuned properly on the new model's you just tell it its lithium lifep04 or lipo or whatever and it auto cuts off things like float charge and it has cold protection cut off to save your cells, there made for lithium , and they are 100% tunable so you can set every parameter to be perfect for your custm voltage battery's too.. they start at around$100us and go to about$350 for the high amp versions for huge solar arrays.. just make sure when buying a controller nowadays that it has a lithium setting thats customisable for your lithium type
Thanks for sharing @Adam Welch ! Have you checked out any of Jehu Garcia's stuff? He is running an electric Samba on a mix of LiFePo batteries, Tesla packs and recycled 18650 cells. He has done a lot of experimentation, as well as the real hard yards of running the cells in his vehicle for years. He's feeling is that you do not need a charge controller or balance charger / BMS. He feels that it is OK to start off with thoroughly tested and balanced cells, then limit the charging voltage to 4 Volt (I think) and to discharge to 3 Volt. He also has fuseable links between cells, so if any portion of the pack exceeds 6 Amps, the link melts and removes the offending cell from the game. He has a video where he tests a pack after running it for 2 years, and the cells are still pretty much balanced. I have also see other guys who follow this route, with the theory that it is best to be over safe on your demands on your pack, without relying on some cheapo chinese components to protect your pack (and house!).
+Douger Rohmer I know of Jehu's videos. He's commented on my channel a time or two as well. I agree once packs get large enough they don't need balancing however I've only got groups of four and they're not perfectly matched. The cell master 7 is working very well and only balances at small currents. Fingers crossed it's not going to cause me any damage any time soon! Thanks for the comments.
Yeah, I guess there is a certain inertia that protects cells in parallel with each other from having wildly differing voltages if there are enough of them.
@@Ziplock9000 not according to Jehu Garcia. I know what you are saying, I myself have a BMS in my 100 AH LiFePO battery pack, but according to him if you test your cells before and bottom balance and/or top balance or whatever, then it's not necessary. He has huge packs which are probably more than a 100 Volt (ie lots in series).
@@dougerrohmer I think what is happening is the random differences between cells are being averaged out in a large parallel pack due to how many cells he has in parallel. Smaller parallel sets would be more likely to succumb to issues though. For example, if you picked 1000 random numbers between 1 and 100, the average of all of them would always be very near 50. However if you only took 10 random numbers between 1 and 100, the average would be a lot more spread out.
Hi I have enjoyed your videos on charging Lithium batteries ( 24v 7p ) can I ask why you had to connect two of your solar panels in series to charge your 7 pack ? I was looking to setting up a solar 24 v system in one of my sheds , so at the moment I am looking to get as much info as possible on the subject
+Brian Horseman Hello. Yes my panels are nominally 12 volt so to ensure the voltage of the panels is higher than the voltage of the battery bank I needed to place two in series. If your panels are nominally 24v then you won't need to bother.
Thanks so much for sharing. I've Just purchased my first 110w Solar Panel for my Tiny Home Build. I've not yet purchased my Solar Charge Controller or Battery set up yet. Would you suggest a regular inexpensive MPPT that you tested ( cpt-la10 solar charge controller ) and Lead Acid, or MPPT and Lithium Batteries, or PMW and Lithium? Thanks for time and much appreciated suggestions.
There are a few things to consider here. Firstly are you happy to go with a 12 or 24 (or 48) volt system? For me, a 12 volt system is best achieved with 12 volt lead acid batteries. 24 volt and above work equally well with lithium or lead acid. So it depends on what you hope to run from your batteries - are you going to slap on an inverter and run everything at 110/230 volt AC, or do you want to use lower voltage DC loads as well, or exclusively? If you're looking to use low voltage DC lighting for example, most off the shelf products are 12 volt although there are some for the 24v trucking market. So you can go most simply and cheaply with a 12v system or you can run 24 volt and convert down to 12 volt for loads that need it. Issue here is losses in conversion. If your solar is going to be the primary source of power then I'd consider whether you want to do it on the cheap, or pay a bit more money for something that might end up a bit more reliable. In my shed if the solar goes down (although having said that I haven't yet had a charge controller fail) I have alternatives available. MPPT vs. PWM is always an interesting debate. MPPT is an advantage if you have somewhere to store the additional power. MPPT charge controllers will end up in PWM mode once the batteries are full. So if your batteries are charged quickly on a morning the MPPT charge controller may be fairly pointless. They may also not be quite as efficient in the winter when power is very low coming from the solar panels. If you look at the cost of MPPT vs. PWM and you have the roof space it may be better to put that extra money into more panels rather than MPPT. However the charge controller you looked at is only slightly more expensive than a reasonable PWM charge controller. However the losses in conversion may be such that a decent PWM charge controller will reap better results. Lead acid batteries are quite good at gobbling up the power you throw at them. With lithium you don't want to charge them too aggressively. So if you go down the route of lithium you need to consider what is the maximum charge you might achieve, and will that be too high for your lithium pack. For both chemistries you need to consider what your typical daily use will be, and will your solar be able to replenish that on a typical winters day. If I was starting again today I would have to seriously consider lithium, however it seems silly to have to convert down to 12 volt as often as I think I would need to for the things I've got running in the shed. My shed roof is now completely covered with panels. The only way to get more power for me now is to use MPPT. Your situation may be very different. Keep watching the videos on youtube and you'll get a sense of what will work best for you.
Adam Welch Mr.Welch, thank you so very very much again, for your time and sharing your, this knowledge, information, testing experience and response. I truly truly appreciate your time and the energy you give. Sun power been an actual dream of mine since I was a child and I will most definite,y be watching. And I look forward to also sharing as I get further along. My aim, is to have a 10'x28' off grid tiny home on wheels accompanied by my portable Yurt, which will be both my additional space and my instant Pop Up Cafe. I will be using all very low wattage dimmable recessed LED lighting. An instant hot water electric or propane heater, there may be a small projection television instead of the traditional flat screen. An induction stove, a cast iron wood stove, air circulation fan intake and exhaust, a LED porch light, a. I'd range stereo system and electric tea kettles. Right now, I'd like to build something to have power for my Mobil small portable bar size cafe tea street cart. Where most products are cold but able to run a small Flojet bottled water pump from 6gallon water tanks, 1 or 2 electric tea kettles, an instant hot water heater (only comes on when in use) and possible, a small home style semi professional espresso machine. In my tiny home will be my Apple Computer editing work station with a 30' HD Apple monitor Laptop speakers. All y security outdoor night lights will be the autonomous LED Solar outdoor light style and I will be looking to Supplement my mobile home shed's power with at least 1 wind turbine (deciding on VAWT or HAWT). Thanks so much, I'll be watching! Happy new year to you and ALL!!!
Hello! Adam Welch, After watching your video series, I decided to do this project to test the 25 volts, I am using a lipo battery voltage tester to monitor the voltage of each cell, Could you help me with respect to the connections between cells in cases holder, in segment 6 to 7 the monitor is missing and presented the value of 6.4v when it should have segment 6 (3.2v) and segment 7 (3.2v ) and the monitor all features 30.3v, I believe that the how to connect the segments is not correct, should have some more detail that I could not see in your video, could send me some link how to connect the segments cells in the holder. Thank you very much
I am going to power a solar charge controller with a 150w 19v power supply.. and was told to stick a diode in the circuit to stop power feeding back in to the power supply.. so was wondering what type of diode to get.. ??? Any help ?? I have tried doing this with wallwarts and it works sometimes. And sometimes it Blow's the AC adapter.. and don't want to risk it with the AC adapter I have now because it's going to be expensive to replace.. I am hoping to make something that can charge an 130 ah lead acid at relatively high amperage.. any help would be appreciated
@Adam Welch The charge controller you have posted the link to is no longer available. Can you suggest any other charge controller that you have tested and works well with 18650 battery packs. Thanks
I'll add this to the description - these are the ones I got from China. rover.ebay.com/rover/1/711-53200-19255-0/1?icep_ff3=2&pub=5575189419&toolid=10001&campid=5337903455&customid=7s+Balanced+Cable&icep_item=381594717286&ipn=psmain&icep_vectorid=229466&kwid=902099&mtid=824&kw=lg
Hi adam I have been using my solar charge controler with 3s set on 12.7v for over 3 years with no issuse. Each cell charges to 12.2333v the same as most digital chargers!
Good explanation, i was planning on running my little 18650 powerwall at 24v, i had wondered with my tracer whether i can have the batteries at 24v but the output at 12v. I shall have to experiment. BTW does the balance lead come with the 7s monitor?
+Colin Hickey (Lets make stuff!) Hey Colin (lets make stuff) :-) and thank you. The monitor doesn't come with a balanced cable but you can get them in packs of ten for about £2 from China or there's a good reseller in the uk I used who sends them quickly for about £1.80 each I think it was. Inhelune his name is - but I've just checked and he is away until September :-( The output in the tracer is just a connection to the battery. That in my opinion is the biggest issue with 24/48 volt systems. You need to either step down or as most do just hook up an inverter - both solutions lead to losses. Thanks again.
Another question. Let's say I want to hook up a 100 Watt panel to this config. The panel I was looking at was 12v. It looks from the datasheet of this controller, that the panel voltage needs to be > battery. So, therefore I would need two 50 watt panels in series to step up the voltage to 24 volts. However, this is still lower than 7s 18650's which would have a nominal voltage of 25.9 - how would this work? I always thought these controllers were programmable so I could step up or down to match whatever I wanted to charge the batteries to. Or do I need to keep looking for a 100 Watt 24 v panel? Sorry, I'm new to solar... :)
+O Messner your panel voltage will need to be higher than your battery voltage. There are a couple of boost MPPT charge controllers, but 99% of all solar charge controllers need higher solar voltage than battery voltage. 12 volt panels actually produce up to around 21-22 volts open circuit and about 17-18.5 volts at their maximum power point. You can double these figures for a '24 volt' panel. So either a single 24 volt panel or two 12 volt panels in series (that's what I'm using for this experiment) will do the job fine for a 7s pack.
+Adam Welch thanks. yeah, looks like I'll pickup a regular full size 300 watt 24 volt panel. A local supplier here has some grade C panels very cheap. I was hoping to keep it small, but the bigger fullsize 24 volt panels are cheaper locally than 70 or 100 Watt.
just a quick question the lg 18650 battery from ebay (Lithium Ion ICR18650 MF1 2150mAh ) 20x cells each cell is 2150 ah. The spec sheet says Max. Charge Current 1.0C(2,150mA). So when you have this pack 36v 10s 2p what is the maximum ah current can you charge it 2ah 42v current or 2ah current x 20 cells ~ 40 ah current at 42v. Now if you have 3x 10s 2p in parallel which is 36v 12.12 ah what is the maximum ah current you can charge thats 60 cells is it 60 cells at 2ah current which is 120 ah current for 60 cells or just 2 ah for 60 cells using cccv charger Thank you very much
Do you think it would work with lithium iron phosphate as well? The voltage numbers are a little different, but some of the other parameters are similar. Constant current for example, and shut off charge When full?
i did this but i was using an old charge controller with 2x usb ports on it.. with a usb battery bank.....i just swoped the batterys when i needed them for something.
Excellent video.. nice to see the coloured charts iv been toying arounf with 3s vs 4s but 7s is clearly the way to go.. typical that i have purchased 12volt inverters - anyway out of this?
Don’t totally discount 3 or 4s if you’ve got 12v inverters. Look at the specs for your inverter and see if 4s will work within their limits. If so, you might be able to edit the settings of your solar charge controller to suit 4s. I like 12v because I’ve got lots of things which use 12v without any conversion. If you’re using ac voltage on most of your stuff the 3/4s issue I highlight here may not effect you.
+Adam Welch - Happy New Year! We've not seen your vids in a while, so hopefully all okay! I'm doing this build at the moment! @9:20 approx. you mention, "with all my batteries in" and then connect up; if I can step back a little, when you connected the 7s balance cables, I take it you connected to each cells negative in the cell box? Just a quick sensor check. It would be really helpful if you commented on wiring sizes too (again as a sensor check) specific to this build or any lessons learned. Hope this is okay! - Aidan
+Aidan McGrath Yeah the balance leads connected to the nickel strip on the negative side of each group. However there is also a connection at the most positive point too - so my 7s pack has eight balanced cables. As for wiring size it all depends on the current you'll be charging or discharging the cells at. I'm using AWG14 to connect to my 10 amp charge controller, but I generally try to over-spec the wiring where I can. The setup is working very well. I've found it to be staying well in balance and charging well. It now survives a few poor days and gobbles up the amps when the sun finally returns.
It was a pity you skipped over the wiring of the Capacity Controller as i was looking for that. The Capacity Controller seems to have 8 leads but you have it connected to 7 batteries so are two of the leads connected to the same battery.
No. With seven cells in series there are eight different points you can connect - and eight different voltages. Starting with the most negative point, then the point between the first cell and the second, the second and the third etc. all the way up to the most positive point at the positive end of the last cell. I think this video goes into it more… Solar Charging Lithium Ion 18650s - Part 2, Getting the balance right - 12v Solar Shed th-cam.com/video/aiVGOEH-T4U/w-d-xo.html
+The Walking Trade Its complicated isn't it... it's not so much the technology - PWM or MPPT that's an issue here. It's the voltage targets at which the charge controllers are set for. All the cheap charge controllers I've come across for lithium cells are two stages chargers and set for 4.2 volts per cell. They do Constant current (or bulk) until the cells get to somewhere close to 4.2 and then they float charge (or constant voltage) at this level. All the commercial lithium charges (none solar) and the cell manufacturers say to charge to 4.2v then once the current drops to 5-10% of the initial current disconnect the charge entirely. These cheap lithium charge controllers keep trickle charging the cells once they're at 4.2v and will continue to do so until the sun goes down. Using a lead acid charge controller actually works better in my opinion. It's got a three stage charge. Bulk, absorb and float. Bulk (CC) is first, then absorb. As long as the absorb level is 4.2v per cell or less that's the charging limit (absorb usually happens for a fixed time in cheap charge controllers rather than it monitoring the battery state per se). The float voltage will be set lower than absorb. So when the cells reach 4.2 and the absorb time is up the cells are left completely off charge until the voltage level drops. So for me the charging profile works better on lead acid charge controllers than 'lithium' ones. Hope that makes sense?
The title was very promissing to me because i have 120 new Panasonic 18650 batteries and i first wanted to connect them in 3 series in my Iveco daily, and hook them up on solar but when i'm driving, my alternator which gives 14,7V will charge them to... but i also read that it's maybe better to put them in 4 series... so i hoped to find the answer in your video.. but then you got to 24 Volts :p and i can see in the green red diagram why you dit that but my iveco is 12V powered. ( i don't think i can do that, or my alternator will get more volts from my leisure battery than it provides.. and that does not sound good i guess ), any idea's suggestions ? :)
Yeah I just don't think 3s or 4s work very well in your typical 12 volt environment. If I could have made it work I would have done in the shed because that's my preferred nominal voltage. 4s will charge up to a maximum of 16.8v but 14.7/4= 3.675 per cell. You'd be massively under charging your cells and continually keeping them below their nominal voltage. I'd suggest you have a couple of options. Change your chemistry - not really an option now you have 120 cells! Or think about DC2DC converters. You could potentially use a DC2DC converter to boost or buck your vans alternator voltage to a more suitable charging voltage for a 3s or 4s pack. You'll need something that starts the process automatically, is protected from reverse current and can handle the amount of current you hope to charge at. Another DC2DC converter might be required to feed your loads in the van if your battery pack is going to be sitting at 16ish volts. I guess you'll also need to grab the most efficient DC2DC converters you can too - otherwise there could be a fair bit of energy (and some fuel) wasted. Hope that helps.
+Doogs Fixit Vids The lithium pack is just for testing. Both are being charged daily even on these grey rainy days. The imax b6 can't charge my 7s lithium pack though...
+Adam Welch Good point. I've watched this with great interest as I'd like my solar shed setup to be lithium based. I'm currently converting a large shed so I can have it as a lab/workshop and want to power it completely by solar and have a lot of harvested cells. Thanks for sharing.
Short version: No, you can't charge 18650's from a lead-acid charger (at least at 12V) because if you do it, the batteries will be over-charged and damaged. Li-Ion batteries need their charging voltage and current regulated far more severely than do lead-acid batteries. You might be able to get away with it at 24V but the battery pack will still not be charged in the manner which is recommended for 18650's, to give their maximum life.
One issue I had with a power pack made of 18650 and a solar back up project (Inverter / Solar panels/ Charge Controller) was that 3 in series is 12v which is ok....But- 4 in series giving 16. + volts was too high for my 400/800 Inverter... It goes to default. BUT- It helps take that "Over Charge" issue... what is the compromise? So- I am wondering about adding a voltage kick down of 12 volts (but- do you lose that extra power? ) To be in line with the Inverter , but what do we do for the over charge problem if that kick down kicks it to 12v ? Damned if ya do.....Damned if ya don't lol
Some LifePO4 AA's are really cheap on ebay... not sure what you'd use them for.. :) I built this a while ago, into the back of a 20w solar panel:- goo.gl/photos/gABAEjberJsybCVw6 20Ah LiFePO4, with battery manager, charge controller, watt meter and DC-DC regulators for 5v and 20v as well as DC charger. :)
James Lewis, I wonder if LiIon / LiFePO4 degrade because of the difference between their charging profiles and lead acid charging profile. I'm not an expert on battery charging, so I might easily be wrong here, but isn't there a significant difference in the way these battery types are charged?
Hi, on Batteryuniversity you showed a sheet about number of expected charge-cycles count before a battery die, and the less Voltage loaded the higher number of cycle you can expect. But this also mean you will need to reload the batteries more time because they will start from 3.92 and not 4.2 for example. So if you need to reload the battery more time then you increase cycle's count faster and finally is it really interesting ?
Ideally you size your batteries and number of panels so that you only need to charge/discharge them between 3.0 and 3.92. More panels/batteries = less cycles.
Yeah I guess it does (not accounting for losses). The watt hours of the bank would remain the same, but as the voltage has reduced the mAh would increase. I guess we also need to factor in that my '24 volt' pack actually has a nominal voltage of 25.9 volts so actually after losses it probably is about double. A good point - thanks.
I did put the wrong numbers as you stated your batteries are 2000 mah I was using the 3500 mah I have listed on my batteries. I have 26650s I am going to build plus I would like to make two packs and parallel them for 14000 mah
Just be careful of "3500 mah" cells. There aren't many manufacturers who can do this, without sacrificing something else somewhere, so they may be fake.
they are 26650s not 18650 but the are radio shack. i do to know if they actually measure 3500mah but they are all the same brand. I don't have any way to verify their true output
Yes, that much is clear. But what voltage do they run the packs at? Yet more curiously, what are the voltage points they use to determine end of charge & end of discharge for each cell? Obviously they want to create a good & reliable product so they surely would have given this careful consideration. Maybe it's a "trade secret"..! lol
Okay, it's been 1.5 years now.... How are your batteries holding up? Question: what wattage panels are you using? as I'm about to change from agm cells to Lithium for longer battery life, I'm concerned about the charging current of your setup when batteries are low as you don't appear to have any current limiting, My panels are 100watters so I don't really want to charge at a possible 6 amps (mppt 17 volts) or higher on a good day.
Adam - I have watched your 18650 battery charging series. Very well done, very informative and educational. I do have a question concerning the entire endeavor. This is in no way a criticism, I suspect I am missing something. You mentioned you had your system setup using lead acid batts. Why replace a working system with the 18650's? It does not appear to be a more cost effective method, the capacity is not greater (obviously that can swing either way depending on implementation). The project looks like a lot of fun and very educational but from a practical stand point I just don't get it. What am I missing? Thanks for your time and I look forward to seeing more of your videos.
Bravo Adam, I have been toying with doing this as I have bulk purchased 18650's. Its a job with the charging/discharging. I think I may follow your project, what would you recommend to get yourself started solar panel size? Also I like your capacity checker, might need to get me one of those. Bless you for sharing, keep up the good work.
I don't think I have any recommendations at the moment - it's very much an experiment. Best not to ever go over 1C charging rate from what I've read, but solar can be so hit and miss - one day you'll get lots of current coming in the next nothing. I've currently 2 '12 volt' 50 watt monocrystaline panels in series which are capable of generating about 2.86 amps at their maximum power point. The cells are brand new 2000mAh Samsungs capable of 20a peak current draw. Thanks for the kind comments
i have watched all your videos about lithium ion solar charge controller, but it seems to me there isnt any decent product that can charge these batteries ? or i m missing something???
+Waseem Javid I think lead acid charge controllers do a pretty good job. Mine has been running over a year now. If you want something to balance as well as charge then there’s only one product I know of - google electrodacus
Adam Welch hi Adam, will the lead acid charge controllers charge at beyond 4.2v? I'm concerned about the life of the batteries as I'm currently attempting to solar power a house on the bangladesh /Indian border!!! One of the remotest, hardest to reach, poorest areas!!! Finding and buying recycled or new batteries from Dhaka and then taking them to the house is not easy if I fry them!!!
It's possible to buy solar charge controllers with no digital meter here from 150 - 400 bdt (about £0.90 - £3.50). They have an input for the solar cell, output to connect your beastly 130amp lead acid battery and two more outputs for lights/sockets. Is it as simple as connecting the diy 18650 pack directly to to the battery output of the controller in the same way you'd connect the lead acid battery?
There's one big problem with your setup, the charger will float charge them when they reach the full status and lithium cells should never be floated. The best setup would be to use a BMS like the one electrodacus designed in his channel or use a proper lithium solar charge controller.
Thanks for your comment - I mentioned the float charge when discussing the difference in charging profiles. I've also mentioned this on a previous video where I reviewed a small pwm lithium ion charge controller ( th-cam.com/video/b3Y3H0I0xec/w-d-xo.html ). This is exactly why I want to try this for myself - I want to monitor whether things do get out of hand, and how quickly. As the float voltage (27.6 volts) is below the boost charge (28.4 volts) I'm interested to find whether the charge controller will actually release the panel entirely. If that's the case then the batteries wont get any more current until they drop to 3.94 volts (27.6/7). Isn't this exciting! :-) Dacian's charge controllers are beautiful things and incredibly well designed from what I have seen. I'd love to get my hands on one but I think this is still a valid experiment in the mean time.
Sorry for not making the question clear, anyway what I meant was how the charge controller knows what current to charge the 18650s with... You can adjust the voltage on the controller by selecting the battery type (AGM, flooded ect) but you can't control the amps being sent to the cells right? I thought the cells might not be able to accept all that current being put into them since most 18650s can only except 1.6A max.
I see - thanks for expanding. As we are dealing with solar there is no guarantees - I did talk about this is the video. The bulk phase will not be constant current. The solar panels I had connected to these 18650s could deliver a maximum of 2.86 amps in perfect conditions (so that is pretty rare) and as we're using a PWM controller it is likely that the panels will not reach their maximum power point. Also that theoretical maximum current is shared across all the seven cells. So in effect we are charging these cells pretty slowly and we're not going near their fully charged capacity. I've expanded this setup now to e 7s4p pack and left the same solar panels on the setup. So I'm charging these even slower now. I guess you need to calculate the maximum charging rate you are comfortable with and connect the right sort of solar array (or panel) to suit.
Are the panels able to provide 2.86 amps, at 24v? Doesn't that mean the cells will have the full (potentially. I use the 2/3rd rule, so realistically 2.86* 2/3rds=) 1.9 amps down through all the cells in series. IE., each cell will have 1.9 amps. Now that you are using, a 4p, this will be 1.9/4, so just under half an amp. But there was the possibility before , for much higher current. Maybe I've made a mis-calculation in my thinking? I would value your input here, as I am looking at doing something similar, but having trouble understanding the charge controller options.
You don't float lithium-ion batteries. just turn off the charge when the current drops, and then restart when the batteries hit a particular lower voltage.
Charging Li Ion cells in series is dangerous since capcity of the cells is never exactly the same. If the cell with lowest capacity is full first >> the voltage on this cell will exceed 4,2V. The same applies for discharge. The cell with lowest capacity will exceed its lowest allowed voltage. Since the cell with lowest capacity gets over-stressed it will even more reduce its capacity and this negative effect to this weakest cell is going to happen earlier. Never ever charge Li Ion cells in series without charge control for each individual cell. Otherwise you could see spontaneous firework.
+Sven Georgi Have you watched the rest of the series? Spoiler alert though... one year on and no fire, no explosions. You’re absolutely right there can be issues, but a well thought out system can run happily for years and the risks can be minimal.
uhm got a easier solution for you. use a portable solar panel like for instance a ALLPOWERS 100W Solar Charger together with for instance a nitecore d4 charger that can run on 12v dc connected to the 18v port via a step down converter.
when charging like i mentioned you'd obviously want to use the batteries in a battery holder like you see at 8:36 instead of making a pack out of them. Charging this way eliminates all troubles with properly charging each individual battery.
if you havent check electrodaus channel, he uses 8 cells in series to charge the cells directly off the panels! th-cam.com/video/1SVA5hAdmJ0/w-d-xo.html
that was so dumb to have to go through so much trouble because you've already got a charge controller. Throw that thing in the trash and get you something that is programmable. Use a 4S pack and short charge it and ur batteries will live forever
I'm really interested to see how an off the shelf lead acid charger works with lithium. I've been running it a year now. The channel is mainly about cheap products and unfortunately the cheap lithium chargers (none programmable) seem to do a far worse job at charging lithium than the lead acid ones do. If my lithium bank gets bigger (and there's a good chance it will) then a programmable solar charge controller will definitely be the way to go. You say dumb, I say interesting! Cheers
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Great shit man!
You are saving a bunch of people from having to do this experiment.
I had already done all this in my head, so I look forward to the results.
its good they are people on youtube, that have knowledge and know what they do
You are great at presenting your experimentation ideas and reasoning behind them. Seems like a great test to me. There are some (really smart and experienced with lithium) folks on the solar panel talk forum who think charging with a pwm is fine - with some of the caveats that you considered. Looking forward to the results.
+Paul Vudmaska Thanks very much Paul. I hope this experiment is useful to many - and it doesn't burn down my shed of cause.
Winter solstice greetings Adam...! First, thank You for all your videos and work... googling this series for the second or third time. Very inspirational...! Started experimenting (again) with solar and batteries.If you have lamps as load, you can couple same types, 2 in series = Voltage divider. Saves on the buck load. The 12/24V setup seems logical, for small projects and lead/18650. It is a good idea, to separate 12 and 24 V systems with different plug/connectors ...just like we have a different plug for mains and rc.
I have worked with "sealed Gel Batteries" for 20+ years. If you open the top around the seam you will find that they do vent! There are little rubber cups over the small holes and a place for them to vent! When they dry out sometimes you can add water and bring them back
This is ons of the best tutorial videos on 18650 hats off to you.
And that’s one of my best comments. Thank you very much :-)
I am a huge fan of lithium cells.... That sla you showed can be replicated with just 12 of those cells!
you selling your old agm batterys
Awesome. This is something I've wondered about for a long time also :)
Well we'll see how it goes! Cheers
Balance/protection boards for liPo and LiFe are becoming very cheap on Ebay...
Hey Adam
First of all I’ve got to say ; great videos ! They are a pleasure to watch, regarding your clear explanations, excellent video and sound quality, your expert level (as far as I can say), your scientific approach and last but not least your independancy !!
I was hoping you could help me out a little bit on my décisions on how to assemble my litium-ion 18650 battery pack out of USED ones, which I already tested with the ZB2L3 modules.
All this to run :
- a 800 W Pump, peak times 3 makes 2400 W
- some phone/camera/notebook chargers 200W
- led lights 200W
- 2 fans of 100 W : 200 W
total power need of approxiately :
Nominal : 1400W ;
Peak : 3000W ;
Respecting the adjustment of the total capacity per parallel ‘layers’, what if I used different cell quantities in parallel ?
Simplified example : 1st serie 5 mAh + 5 mAh + 5 mAh + 5 mAh + 5 mAh = 25 mAh
2nd serie 6 mAh + 7 mAh + 6 mAh + 6 mAh = 25 mAh
3rd serie 8 mAh + 8 mAh + 9 mAh = 25 mAh
4th serie 12 mAh + 13 mAh = 25 mAh
5th serie 4 mAh + 4 mAh + 4 mAh + 4 mAh + 4 mAh + 5 mAh = 25 mAh
6th serie 3 mAh + 3 mAh + 3 mAh + 3 mAh + 3 mAh + 3 mAh + 3 mAh + 4 mAh = 25 mAh
I figure that if I’d compose my pack like this, the cells are unevenly applied to when charging or discharging, so, as long as I make sure that I have enough of ‘m in parallel (so NOT like the 4th serie in the example), I ‘d eliminate the chance of extracting to many Amps at once out of a single few of them, resulting in overheating and or damage.
Considering my needs, could I determine the size of my battery according to a maximum Amperage demand of 2C per cell?
Let’s say, in a 24 V battery system,according to my needs, I’d need a maximum peak amparage capacity of 125 Amps (3000W devided by 24V). Every single one of the 6 series needs to be able to supply 125 Amps. If 2C equals 125 Amps, Then, C equals 67.5, lets round that up to 68 Amps. Considering that my first question would not be discouraged, one series could consist of 34 cells of 2000 mAh, a second layer could for example consist of 68 1000 mAh cells…, a third of 46 cells of 1500 mAH and so forth……
In total, this would come to a 24 V, 68 Ah battery pack of 1.6 kW…
As it comes to solar charging, what affordable solar charger could you advise, according to my needs ?
As it comes to converting to 220V AC, what affordable converter could you advise, according to my needs ?
Do you recommend to reduce the ampérages by assembling a 48 V Battery ?
Thanx in advance
Now I have a plan. Brilliant idea and I will most certainly be having a talk to myself in the shed over this! Just need a good DCDC 24-12v transformer
I'm glad to have inspired - I'm looking forward to your videos on the subject.
+Adam Welch soon! just got 4 weeks left of 12 hour days then I should be back in the shed. Also my potential lead on recycled laptop batteries has gone silent.
+pietkaify shame about the batteries. I got this lot from nkon. I think it was one of your videos that put me on to them so thanks very much for that.
what was your experience with Nkon? Someone said they didn't have a good time delivery wise
+pietkaify They took about a week I think. Can't fault them to be honest. Was I lucky then?
this is an awesome project i been wondering abot using my lead acid solar charger to charge 18650 thank you for that
Just watched all the the videos in this series they are brilliant just what I’ve been looking for
Really pleased they’ve been useful. There is still some way to go with this setup - I’ve got a few ideas when time allows.
Nice and simple solution!
I have heard the capacity tester might be parasitically drawing more power from the first cell. Just something to have in the back of your head if you do see some cells drifting.
EDIT: I now see you added balancing with tis device in part 3, so this turns into more of a note to others/other projects instead, and perhaps for other (similar) products.
+Dennis Olsson Thanks for the comments (and update) Dennis.
For anyone intrested. They now do a EPsolar Viewstar VS1024BN, with voltages which can configured "custom". Haven't tested it but should allow for a 12v battery combination.
What made you give up on the CN3722 MPPT charger board? Was it the advantage of monitoring the voltage or load protection features? I suppose you would need a BMS to keep the cells from going too low.
+slash2314 I've not given up on the CN3722. It's not a fully featured charge controller though really and as you point out there is no load control and a danger of the cells discharging too much.
This experiment isn't for permanent installation and I can't see me moving to lithium ion in the shed - everything I run is 12 volt and as I found out in the video lithium cells can't really replace a 12 volt system.
Adam, My PWM solar charger has "FLOAT", "DISCHARGE STOP" and "DISCHARGE RECONNECT". I have set 29V - "FLOAT", 21V - "DISCHARGE STOP". What voltage should I use for DISCHARGE RECONNECT.
Thanks, I really enjoy the educational value I get out of your videos.
It will need to be set above your discharge stop voltage. It’s the voltage at which you’re happy to start draining the pack again. So loads are switched off at 21v currently and you may set you reconnect voltage to 24v for example. Thanks for the kind comments.
I'm pretty sure float charging (Trickle) will damage the cells. I know it will at 4.2V but I'm not sure if it will or not at a lower voltage. Either way this video came at just the right time as I was literally researching just this all day. The best solution I could come up with was an MPPT charge controller from Genasun. They are able to make custom voltages for you and they even have a voltage step up on one of their models (Perfect for my 14S pack), quite pricey though. Will definitely watch for the follow up video. As well as any other video pertaining to solar and li-ion.
+lonnie776 Quite a lot of MPPT chargers have the facility to change the charging parameters (and a fair few pwm too) but they all still work on the bulk, absorb, float charging cycle where as lithium need CC/CV. This is the test here really.
The only other step up controller I've seen was the Minghe MPPT solar charge controller Julian Ilett reviewed a few weeks ago. Take half an hour to watch his videos on that... I found it very interesting.
***** Oh I guess I forgot to mention they Genasun controllers have specific models designed for LiFePO4 and Li-ion.
Greetings from finland. I've almost ready to test my setup based on yours. I have Victron Solar Solarcontroller model 75V/15A with bluetooth, so i can monitor and change values from tablet or phone. It has greater setup area and its MPPT (Maximum Power Point Tracking) rather than PWM controller. MPPT hides the load from solarpanels, so it may boost the power output about 10-20% I've load the Victron without battery with 12V mini refrigerator which runs draws at 50-60W with 12V from solar and 72W with 240V AC. Works fine, until gray-area of the clouds emerge :). So i need a little backup from my rig. The rig is on a tandem-bike hooked trailer (800mm x 600mm x 415mm 165 liter capacity, watertight). Im planning to use that trailer as mobile power station in trips. I've already tested to load all kinds of things via Solarpanels and overall it looks good to me.
Nice I will look forward to the follow up video. I have been thinking about doing something like this. Cheers.
Fantastic video. This is EXACTLY what I was thinking about today for an off grid 7.5 watt (24x7) load. Except, I will double by battery capacity in parallel. I'll be using a 70W panel. I didn't want to use lead acid due to size/bulkiness. Amazing that I found this video as surprisingly, there's not much on this exact subject (charging 18650's with regular solar charge controller)
Are you using the individual cell voltage monitor for safety (verifying periodically you don't have one cell that is way under voltage)? In my reading, it sounded like the more of these 18650's you have in series, it becomes more of a potential safety issue.
Also, can this controller just be set to have a load 24x7? I will always have a load, just need the excess power to dump into the battery for night time.
Phoenix, USA
+O Messner Thanks for the kind words. Yes the charge controller can be set to have the load on all the time.
I'm keeping an eye on the cell voltages to see if they go out of balance or if any go worryingly high or low. More to come soon on this.
I can help with this - I think I may have already contacted you about my low-cost arduino PWM charge controller circuit? It's perfectly capable of charging li-ions, as charge voltage and current can both be monitored and controlled via software. Just program it for whatever chemistry battery you are using. You'll need to add a balance circuit to the battery if you want the cells to last well though.
Hello - yes you've sent me the info about your clever little charger. I intend to build one soon. This experiment is all about using an off the shelf product for something it wasn't fully intended for however - it's an experiment and there will be better ways to do it. Balancing is something I expected to need from the start - an update video to come soon.
Very useful information as to the first steps in working with Solar and 18650s, thanks!
+Stephen Ludgate Cheers
Can I ask details about the step down controller @9:03
I like that. Li-ion are much better choice then lead-acid. But shouldn't you get a 7s protection board? I mean if one of this cells is not balanced it might blow. I've seen some on ebay.
Well that is what experimentation is all about! I may well need a protection board - one of the things I hope to find out. All the cells are brand new, from the same supplier, all have a similar internal resistance - I might just get away with it!
I guess it should work but over time you might get into trouble as the batteries will get unbalanced. I seen 4S pack protection board dirt cheap on ebay. but the problem is you have to apply a constant voltage (i.e 16.8 for 4S pack) so some kind of boost/buck converter might be needed. Anyway it is very cool.
Yup, I agree. Some extra losses but I would like you to be on on the safe side. Also make sure that even protection boards are not a 100% safety warranty. This weekend I was charging some 2000mAh cells and 2 kept on charging it seems. I couldn't touch them anymore, they got extremely hot. The lii-500 charger reported 38XXmAh charge and they were at 4.18V . Took them out and the voltage dropped to 3.98V instantly. They are now outside in the shade for safety reasons.
Yours might be all good and stable now but a protection board and a temp monitor controlled by arduino or so might be a better bet for the future.
+Luc Peeters Thanks for your comments Luc. I expect you will be right, but I'd like to run a little while without and see how it goes.
These cells are new - from a reputable supplier and from tests I've run have a low internal resistance and their rated capacity. I think I'm in the best position to get away with this. Reclaimed cells could be more problematic - another day another test I guess.
***** over discharge is also a problem. +Luc Peeters A temperature sensor and arduino is very easy to implement but you have to control the power so this becomes a battery charger which you can buy ready made with dedicated chip.
Hi, I'm all set to start building this but have a couple more questions. Firstly, what amp version of the solar charge controller did you go for as there seems to be multiple versions. Secondly, did it automatically switch to 24v or do you have to set it in the settings as you did with the Gel battery type.
Ep ever auto knows when you connect your batteries if its 12 or 24v, but it can only do those 2, you need the other version for 24 to 48v but they are the same except the 24 to 48 can handle double the watt's of the 12 to 24 in solar input and in charge amperage, the video your watching is very outdated for charge controllers, i bought the epever an tracer 40 amp 2 years ago and its mppt with an mt50 controller thats remote mountabke for tuning and for a monitoring screen where ever you want to mount it.. they are lightyears ahead of this old version and i am needing to upgrade it now, so i suggest just buying a new version of either epever victron or renogy branded one because they are all the same price range and the cheapest quality ones , they come in lithium version now, so they can be fully tuned properly on the new model's you just tell it its lithium lifep04 or lipo or whatever and it auto cuts off things like float charge and it has cold protection cut off to save your cells, there made for lithium , and they are 100% tunable so you can set every parameter to be perfect for your custm voltage battery's too.. they start at around$100us and go to about$350 for the high amp versions for huge solar arrays.. just make sure when buying a controller nowadays that it has a lithium setting thats customisable for your lithium type
Thanks for sharing @Adam Welch ! Have you checked out any of Jehu Garcia's stuff? He is running an electric Samba on a mix of LiFePo batteries, Tesla packs and recycled 18650 cells. He has done a lot of experimentation, as well as the real hard yards of running the cells in his vehicle for years. He's feeling is that you do not need a charge controller or balance charger / BMS. He feels that it is OK to start off with thoroughly tested and balanced cells, then limit the charging voltage to 4 Volt (I think) and to discharge to 3 Volt. He also has fuseable links between cells, so if any portion of the pack exceeds 6 Amps, the link melts and removes the offending cell from the game. He has a video where he tests a pack after running it for 2 years, and the cells are still pretty much balanced. I have also see other guys who follow this route, with the theory that it is best to be over safe on your demands on your pack, without relying on some cheapo chinese components to protect your pack (and house!).
+Douger Rohmer I know of Jehu's videos. He's commented on my channel a time or two as well. I agree once packs get large enough they don't need balancing however I've only got groups of four and they're not perfectly matched.
The cell master 7 is working very well and only balances at small currents. Fingers crossed it's not going to cause me any damage any time soon!
Thanks for the comments.
Yeah, I guess there is a certain inertia that protects cells in parallel with each other from having wildly differing voltages if there are enough of them.
@@dougerrohmer If they are wired in parallel they simply can't go out of balance. It's in series where they can, and often do go out of balance.
@@Ziplock9000 not according to Jehu Garcia. I know what you are saying, I myself have a BMS in my 100 AH LiFePO battery pack, but according to him if you test your cells before and bottom balance and/or top balance or whatever, then it's not necessary. He has huge packs which are probably more than a 100 Volt (ie lots in series).
@@dougerrohmer I think what is happening is the random differences between cells are being averaged out in a large parallel pack due to how many cells he has in parallel. Smaller parallel sets would be more likely to succumb to issues though. For example, if you picked 1000 random numbers between 1 and 100, the average of all of them would always be very near 50. However if you only took 10 random numbers between 1 and 100, the average would be a lot more spread out.
Hi I have enjoyed your videos on charging Lithium batteries ( 24v 7p ) can I ask why you had to connect two of your solar panels in series to charge your 7 pack ?
I was looking to setting up a solar 24 v system in one of my sheds , so at the moment I am looking to get as much info as possible on the subject
+Brian Horseman Hello. Yes my panels are nominally 12 volt so to ensure the voltage of the panels is higher than the voltage of the battery bank I needed to place two in series. If your panels are nominally 24v then you won't need to bother.
Thanks so much for sharing. I've Just purchased my first 110w Solar Panel for my Tiny Home Build. I've not yet purchased my Solar Charge Controller or Battery set up yet. Would you suggest a regular inexpensive MPPT that you tested ( cpt-la10 solar charge controller ) and Lead Acid, or MPPT and Lithium Batteries, or PMW and Lithium? Thanks for time and much appreciated suggestions.
There are a few things to consider here. Firstly are you happy to go with a 12 or 24 (or 48) volt system? For me, a 12 volt system is best achieved with 12 volt lead acid batteries. 24 volt and above work equally well with lithium or lead acid.
So it depends on what you hope to run from your batteries - are you going to slap on an inverter and run everything at 110/230 volt AC, or do you want to use lower voltage DC loads as well, or exclusively? If you're looking to use low voltage DC lighting for example, most off the shelf products are 12 volt although there are some for the 24v trucking market. So you can go most simply and cheaply with a 12v system or you can run 24 volt and convert down to 12 volt for loads that need it. Issue here is losses in conversion.
If your solar is going to be the primary source of power then I'd consider whether you want to do it on the cheap, or pay a bit more money for something that might end up a bit more reliable. In my shed if the solar goes down (although having said that I haven't yet had a charge controller fail) I have alternatives available.
MPPT vs. PWM is always an interesting debate. MPPT is an advantage if you have somewhere to store the additional power. MPPT charge controllers will end up in PWM mode once the batteries are full. So if your batteries are charged quickly on a morning the MPPT charge controller may be fairly pointless. They may also not be quite as efficient in the winter when power is very low coming from the solar panels. If you look at the cost of MPPT vs. PWM and you have the roof space it may be better to put that extra money into more panels rather than MPPT. However the charge controller you looked at is only slightly more expensive than a reasonable PWM charge controller. However the losses in conversion may be such that a decent PWM charge controller will reap better results.
Lead acid batteries are quite good at gobbling up the power you throw at them. With lithium you don't want to charge them too aggressively. So if you go down the route of lithium you need to consider what is the maximum charge you might achieve, and will that be too high for your lithium pack. For both chemistries you need to consider what your typical daily use will be, and will your solar be able to replenish that on a typical winters day.
If I was starting again today I would have to seriously consider lithium, however it seems silly to have to convert down to 12 volt as often as I think I would need to for the things I've got running in the shed. My shed roof is now completely covered with panels. The only way to get more power for me now is to use MPPT. Your situation may be very different.
Keep watching the videos on youtube and you'll get a sense of what will work best for you.
Adam Welch Mr.Welch, thank you so very very much again, for your time and sharing your, this knowledge, information, testing experience and response. I truly truly appreciate your time and the energy you give. Sun power been an actual dream of mine since I was a child and I will most definite,y be watching. And I look forward to also sharing as I get further along. My aim, is to have a 10'x28' off grid tiny home on wheels accompanied by my portable Yurt, which will be both my additional space and my instant Pop Up Cafe.
I will be using all very low wattage dimmable recessed LED lighting. An instant hot water electric or propane heater, there may be a small projection television instead of the traditional flat screen. An induction stove, a cast iron wood stove, air circulation fan intake and exhaust, a LED porch light, a. I'd range stereo system and electric tea kettles. Right now, I'd like to build something to have power for my Mobil small portable bar size cafe tea street cart. Where most products are cold but able to run a small Flojet bottled water pump from 6gallon water tanks, 1 or 2 electric tea kettles, an instant hot water heater (only comes on when in use) and possible, a small home style semi professional espresso machine. In my tiny home will be my Apple Computer editing work station with a 30' HD Apple monitor Laptop speakers. All y security outdoor night lights will be the autonomous LED Solar outdoor light style and I will be looking to Supplement my mobile home shed's power with at least 1 wind turbine (deciding on VAWT or HAWT). Thanks so much, I'll be watching! Happy new year to you and ALL!!!
Hello! Adam Welch,
After watching your video series, I decided to do this project to test the 25 volts, I am using a lipo battery voltage tester to monitor the voltage of each cell,
Could you help me with respect to the connections between cells in cases holder, in segment 6 to 7 the monitor is missing and presented the value of 6.4v when it should have segment 6 (3.2v) and segment 7 (3.2v ) and the monitor all features 30.3v, I believe that the how to connect the segments is not correct, should have some more detail that I could not see in your video, could send me some link how to connect the segments cells in the holder. Thank you very much
I am going to power a solar charge controller with a 150w 19v power supply.. and was told to stick a diode in the circuit to stop power feeding back in to the power supply.. so was wondering what type of diode to get.. ??? Any help ?? I have tried doing this with wallwarts and it works sometimes. And sometimes it Blow's the AC adapter.. and don't want to risk it with the AC adapter I have now because it's going to be expensive to replace.. I am hoping to make something that can charge an 130 ah lead acid at relatively high amperage.. any help would be appreciated
@Adam Welch The charge controller you have posted the link to is no longer available. Can you suggest any other charge controller that you have tested and works well with 18650 battery packs. Thanks
Very educational video on n interesting subject. Thank you bro
do you have a link for the balance lead, not sure if the capacity tester comes with one, cheers
I'll add this to the description - these are the ones I got from China. rover.ebay.com/rover/1/711-53200-19255-0/1?icep_ff3=2&pub=5575189419&toolid=10001&campid=5337903455&customid=7s+Balanced+Cable&icep_item=381594717286&ipn=psmain&icep_vectorid=229466&kwid=902099&mtid=824&kw=lg
Could you maybe do a Controller comparison (ones you already have)
Just viewed video as I have this controller on a boat IU have just bought - what size solar panel could I use to keep my 3 batteries at charge
Hi, where did you get the "Molex Plug-in w/7 pairs of leeds" ? I want my dad to by for me. Please let me know. thanks Jimmy
+BWWGL9 I guess you mean the 7s balance cable? There's a link in the description if so.
Thanks for the reply appreciate it cheers Shane
what is that black box whice is between the red cable?
Hi adam I have been using my solar charge controler with 3s set on 12.7v for over 3 years with no issuse.
Each cell charges to 12.2333v the same as most digital chargers!
Nice clear explanation. What solar controller/module would you suggest for charging 10,000mah battery bank with micro usb input?
If your charge controller has battery temperature compensation it might be possible to mess with that to fine tune voltages.
Good explanation. very useful .
Good explanation, i was planning on running my little 18650 powerwall at 24v, i had wondered with my tracer whether i can have the batteries at 24v but the output at 12v. I shall have to experiment. BTW does the balance lead come with the 7s monitor?
+Colin Hickey (Lets make stuff!) Hey Colin (lets make stuff) :-) and thank you.
The monitor doesn't come with a balanced cable but you can get them in packs of ten for about £2 from China or there's a good reseller in the uk I used who sends them quickly for about £1.80 each I think it was. Inhelune his name is - but I've just checked and he is away until September :-(
The output in the tracer is just a connection to the battery. That in my opinion is the biggest issue with 24/48 volt systems. You need to either step down or as most do just hook up an inverter - both solutions lead to losses.
Thanks again.
Another question. Let's say I want to hook up a 100 Watt panel to this config. The panel I was looking at was 12v. It looks from the datasheet of this controller, that the panel voltage needs to be > battery. So, therefore I would need two 50 watt panels in series to step up the voltage to 24 volts. However, this is still lower than 7s 18650's which would have a nominal voltage of 25.9 - how would this work? I always thought these controllers were programmable so I could step up or down to match whatever I wanted to charge the batteries to. Or do I need to keep looking for a 100 Watt 24 v panel? Sorry, I'm new to solar... :)
+O Messner your panel voltage will need to be higher than your battery voltage. There are a couple of boost MPPT charge controllers, but 99% of all solar charge controllers need higher solar voltage than battery voltage.
12 volt panels actually produce up to around 21-22 volts open circuit and about 17-18.5 volts at their maximum power point. You can double these figures for a '24 volt' panel.
So either a single 24 volt panel or two 12 volt panels in series (that's what I'm using for this experiment) will do the job fine for a 7s pack.
+Adam Welch thanks. yeah, looks like I'll pickup a regular full size 300 watt 24 volt panel. A local supplier here has some grade C panels very cheap. I was hoping to keep it small, but the bigger fullsize 24 volt panels are cheaper locally than 70 or 100 Watt.
Which charge controller do you recomend ? thats a decent price 10/20 amp
just a quick question the lg 18650 battery from ebay (Lithium Ion ICR18650 MF1 2150mAh ) 20x cells each cell is 2150 ah. The spec sheet says Max. Charge Current 1.0C(2,150mA). So when you have this pack 36v 10s 2p what is the maximum ah current can you charge it 2ah 42v current or 2ah current x 20 cells ~ 40 ah current at 42v. Now if you have 3x 10s 2p in parallel which is 36v 12.12 ah what is the maximum ah current you can charge thats 60 cells is it 60 cells at 2ah current which is 120 ah current for 60 cells or just 2 ah for 60 cells using cccv charger
Thank you very much
Do you think it would work with lithium iron phosphate as well? The voltage numbers are a little different, but some of the other parameters are similar. Constant current for example, and shut off charge When full?
i did this but i was using an old charge controller with 2x usb ports on it.. with a usb battery bank.....i just swoped the batterys when i needed them for something.
whats abou cell balancing ? why do you dont use a 7S BMS ?
Excellent video.. nice to see the coloured charts iv been toying arounf with 3s vs 4s but 7s is clearly the way to go.. typical that i have purchased 12volt inverters - anyway out of this?
Don’t totally discount 3 or 4s if you’ve got 12v inverters. Look at the specs for your inverter and see if 4s will work within their limits. If so, you might be able to edit the settings of your solar charge controller to suit 4s. I like 12v because I’ve got lots of things which use 12v without any conversion. If you’re using ac voltage on most of your stuff the 3/4s issue I highlight here may not effect you.
@@AdamWelchUK Thankyou, I will.
How many batteries for a practical use in a shed?
+Adam Welch - Happy New Year! We've not seen your vids in a while, so hopefully all okay! I'm doing this build at the moment! @9:20 approx. you mention, "with all my batteries in" and then connect up; if I can step back a little, when you connected the 7s balance cables, I take it you connected to each cells negative in the cell box? Just a quick sensor check. It would be really helpful if you commented on wiring sizes too (again as a sensor check) specific to this build or any lessons learned. Hope this is okay! - Aidan
+Aidan McGrath Yeah the balance leads connected to the nickel strip on the negative side of each group. However there is also a connection at the most positive point too - so my 7s pack has eight balanced cables.
As for wiring size it all depends on the current you'll be charging or discharging the cells at. I'm using AWG14 to connect to my 10 amp charge controller, but I generally try to over-spec the wiring where I can.
The setup is working very well. I've found it to be staying well in balance and charging well. It now survives a few poor days and gobbles up the amps when the sun finally returns.
Were do yo buy the magnets please thanks Shane
Neodymium Magnets are available in all kids of shapes and sizes pretty cheaply on Ebay: goo.gl/WLB1VB
It was a pity you skipped over the wiring of the Capacity Controller as i was looking for that. The Capacity Controller seems to have 8 leads but you have it connected to 7 batteries so are two of the leads connected to the same battery.
No. With seven cells in series there are eight different points you can connect - and eight different voltages. Starting with the most negative point, then the point between the first cell and the second, the second and the third etc. all the way up to the most positive point at the positive end of the last cell.
I think this video goes into it more… Solar Charging Lithium Ion 18650s - Part 2, Getting the balance right - 12v Solar Shed
th-cam.com/video/aiVGOEH-T4U/w-d-xo.html
I don't understand you said that PWM charge controller is not suited for Li-ion (Anself video) ?!
+The Walking Trade Its complicated isn't it... it's not so much the technology - PWM or MPPT that's an issue here. It's the voltage targets at which the charge controllers are set for.
All the cheap charge controllers I've come across for lithium cells are two stages chargers and set for 4.2 volts per cell. They do Constant current (or bulk) until the cells get to somewhere close to 4.2 and then they float charge (or constant voltage) at this level. All the commercial lithium charges (none solar) and the cell manufacturers say to charge to 4.2v then once the current drops to 5-10% of the initial current disconnect the charge entirely. These cheap lithium charge controllers keep trickle charging the cells once they're at 4.2v and will continue to do so until the sun goes down.
Using a lead acid charge controller actually works better in my opinion. It's got a three stage charge. Bulk, absorb and float. Bulk (CC) is first, then absorb. As long as the absorb level is 4.2v per cell or less that's the charging limit (absorb usually happens for a fixed time in cheap charge controllers rather than it monitoring the battery state per se). The float voltage will be set lower than absorb. So when the cells reach 4.2 and the absorb time is up the cells are left completely off charge until the voltage level drops. So for me the charging profile works better on lead acid charge controllers than 'lithium' ones. Hope that makes sense?
Thank you very much for this explanation
The title was very promissing to me because i have 120 new Panasonic 18650 batteries and i first wanted to connect them in 3 series in my Iveco daily, and hook them up on solar but when i'm driving, my alternator which gives 14,7V will charge them to... but i also read that it's maybe better to put them in 4 series... so i hoped to find the answer in your video.. but then you got to 24 Volts :p and i can see in the green red diagram why you dit that but my iveco is 12V powered. ( i don't think i can do that, or my alternator will get more volts from my leisure battery than it provides.. and that does not sound good i guess ), any idea's suggestions ? :)
Yeah I just don't think 3s or 4s work very well in your typical 12 volt environment. If I could have made it work I would have done in the shed because that's my preferred nominal voltage.
4s will charge up to a maximum of 16.8v but 14.7/4= 3.675 per cell. You'd be massively under charging your cells and continually keeping them below their nominal voltage.
I'd suggest you have a couple of options. Change your chemistry - not really an option now you have 120 cells! Or think about DC2DC converters. You could potentially use a DC2DC converter to boost or buck your vans alternator voltage to a more suitable charging voltage for a 3s or 4s pack. You'll need something that starts the process automatically, is protected from reverse current and can handle the amount of current you hope to charge at. Another DC2DC converter might be required to feed your loads in the van if your battery pack is going to be sitting at 16ish volts.
I guess you'll also need to grab the most efficient DC2DC converters you can too - otherwise there could be a fair bit of energy (and some fuel) wasted.
Hope that helps.
Another good video but I would just use the solar on a 12v lead acid and run an IMAX B6 charger running off that to charge the lithium pack.
+Doogs Fixit Vids The lithium pack is just for testing. Both are being charged daily even on these grey rainy days. The imax b6 can't charge my 7s lithium pack though...
+Adam Welch Good point. I've watched this with great interest as I'd like my solar shed setup to be lithium based. I'm currently converting a large shed so I can have it as a lab/workshop and want to power it completely by solar and have a lot of harvested cells. Thanks for sharing.
same here for my 12V solar setup
Great vlogs.... think it’s funny how you point at everting 😂😂
hmm
Short version: No, you can't charge 18650's from a lead-acid charger (at least at 12V) because if you do it, the batteries will be over-charged and damaged. Li-Ion batteries need their charging voltage and current regulated far more severely than do lead-acid batteries. You might be able to get away with it at 24V but the battery pack will still not be charged in the manner which is recommended for 18650's, to give their maximum life.
Unless of course the controller has user modes so you can change the voltage levels which many do these days.
One issue I had with a power pack made of 18650 and a solar back up project (Inverter / Solar panels/ Charge Controller) was that 3 in series is 12v which is ok....But- 4 in series giving 16. + volts was too high for my 400/800 Inverter... It goes to default. BUT- It helps take that "Over Charge" issue... what is the compromise?
So- I am wondering about adding a voltage kick down of 12 volts (but- do you lose that extra power? ) To be in line with the Inverter , but what do we do for the over charge problem if that kick down kicks it to 12v ? Damned if ya do.....Damned if ya don't lol
why not use a DC to DC converter to get your fixed charge voltage, then wire it to a lithium charge control/bms board?
LIFePO4 cells tend to be more compatible with lead acid, since 4 cells has a charge complete voltage of 14.4v
Yeah that is true. Sadly I don't have a supply of LiFePO4 though, they don't put them in laptop batteries.
Some LifePO4 AA's are really cheap on ebay... not sure what you'd use them for.. :) I built this a while ago, into the back of a 20w solar panel:- goo.gl/photos/gABAEjberJsybCVw6
20Ah LiFePO4, with battery manager, charge controller, watt meter and DC-DC regulators for 5v and 20v as well as DC charger. :)
James Lewis, I wonder if LiIon / LiFePO4 degrade because of the difference between their charging profiles and lead acid charging profile. I'm not an expert on battery charging, so I might easily be wrong here, but isn't there a significant difference in the way these battery types are charged?
Hi, on Batteryuniversity you showed a sheet about number of expected charge-cycles count before a battery die, and the less Voltage loaded the higher number of cycle you can expect.
But this also mean you will need to reload the batteries more time because they will start from 3.92 and not 4.2 for example.
So if you need to reload the battery more time then you increase cycle's count faster and finally is it really interesting ?
Ideally you size your batteries and number of panels so that you only need to charge/discharge them between 3.0 and 3.92. More panels/batteries = less cycles.
I was wondering? after the 12 volt converter does the mah stay at 3500 or does it go up to the 7000 mah, math shows it should be?
Yeah I guess it does (not accounting for losses). The watt hours of the bank would remain the same, but as the voltage has reduced the mAh would increase. I guess we also need to factor in that my '24 volt' pack actually has a nominal voltage of 25.9 volts so actually after losses it probably is about double. A good point - thanks.
I did put the wrong numbers as you stated your batteries are 2000 mah I was using the 3500 mah I have listed on my batteries. I have 26650s I am going to build plus I would like to make two packs and parallel them for 14000 mah
Just be careful of "3500 mah" cells. There aren't many manufacturers who can do this, without sacrificing something else somewhere, so they may be fake.
they are 26650s not 18650 but the are radio shack. i do to know if they actually measure 3500mah but they are all the same brand. I don't have any way to verify their true output
John Lucero
I have some of the 26650 cells from Radio shack. I haven't got to use them yet. are they any good?
I wonder what voltage levels of charge & discharge they use in the Tesla battery?
+xanataph Would be interested to know. Not sure anyone I know could afford one though!
+Adam Welch Tesla Batterie consist of 18560 Batterie s
Yes, that much is clear. But what voltage do they run the packs at? Yet more curiously, what are the voltage points they use to determine end of charge & end of discharge for each cell? Obviously they want to create a good & reliable product so they surely would have given this careful consideration. Maybe it's a "trade secret"..! lol
Check out Jehu Garcia's channel. He is using Tesla battery packs in his Samba.
Okay, it's been 1.5 years now.... How are your batteries holding up?
Question: what wattage panels are you using? as I'm about to change from agm cells to Lithium for longer battery life, I'm concerned about the charging current of your setup when batteries are low as you don't appear to have any current limiting, My panels are 100watters so I don't really want to charge at a possible 6 amps (mppt 17 volts) or higher on a good day.
What fuse did you use?
Can I ask you what you think would be the easiest set up to charge my DeWalt lithium ion batteries by solar power .
⚡☀〰〰🔋⚡
✌ From Upper Michigan 🇺🇸
Have you compared the voltage readings on the Capacity meter with your digital meter?
I did because I remember Julian Ilett suggesting to me that he was concerned about accuracy. I found it was pretty good when I tested.
Where'd you get those magnets?
How do you test the MAH?
+INVISIBLE SUN Either using my Arduino capacity checker or a LiitoKala Engineer Lii-300 both of which I've done videos on.
Adam - I have watched your 18650 battery charging series. Very well done, very informative and educational. I do have a question concerning the entire endeavor. This is in no way a criticism, I suspect I am missing something. You mentioned you had your system setup using lead acid batts. Why replace a working system with the 18650's? It does not appear to be a more cost effective method, the capacity is not greater (obviously that can swing either way depending on implementation). The project looks like a lot of fun and very educational but from a practical stand point I just don't get it. What am I missing? Thanks for your time and I look forward to seeing more of your videos.
Bravo Adam, I have been toying with doing this as I have bulk purchased 18650's. Its a job with the charging/discharging.
I think I may follow your project, what would you recommend to get yourself started solar panel size? Also I like your capacity checker, might need to get me one of those.
Bless you for sharing, keep up the good work.
I don't think I have any recommendations at the moment - it's very much an experiment. Best not to ever go over 1C charging rate from what I've read, but solar can be so hit and miss - one day you'll get lots of current coming in the next nothing.
I've currently 2 '12 volt' 50 watt monocrystaline panels in series which are capable of generating about 2.86 amps at their maximum power point. The cells are brand new 2000mAh Samsungs capable of 20a peak current draw.
Thanks for the kind comments
What about making a battery a copper aluminium salt water battery and see if it charges
i have watched all your videos about lithium ion solar charge controller, but it seems to me there isnt any decent product that can charge these batteries ? or i m missing something???
+Waseem Javid I think lead acid charge controllers do a pretty good job. Mine has been running over a year now. If you want something to balance as well as charge then there’s only one product I know of - google electrodacus
Adam Welch hi Adam, will the lead acid charge controllers charge at beyond 4.2v? I'm concerned about the life of the batteries as I'm currently attempting to solar power a house on the bangladesh /Indian border!!! One of the remotest, hardest to reach, poorest areas!!! Finding and buying recycled or new batteries from Dhaka and then taking them to the house is not easy if I fry them!!!
It's possible to buy solar charge controllers with no digital meter here from 150 - 400 bdt (about £0.90 - £3.50). They have an input for the solar cell, output to connect your beastly 130amp lead acid battery and two more outputs for lights/sockets. Is it as simple as connecting the diy 18650 pack directly to to the battery output of the controller in the same way you'd connect the lead acid battery?
Well reasoned.
Excellent, thank you
Great job !
Thanks this was rely helpful
làm sao để có thể mua nó
Great video.. Many thanks..!
There's one big problem with your setup, the charger will float charge them when they reach the full status and lithium cells should never be floated. The best setup would be to use a BMS like the one electrodacus designed in his channel or use a proper lithium solar charge controller.
Thanks for your comment - I mentioned the float charge when discussing the difference in charging profiles. I've also mentioned this on a previous video where I reviewed a small pwm lithium ion charge controller ( th-cam.com/video/b3Y3H0I0xec/w-d-xo.html ). This is exactly why I want to try this for myself - I want to monitor whether things do get out of hand, and how quickly.
As the float voltage (27.6 volts) is below the boost charge (28.4 volts) I'm interested to find whether the charge controller will actually release the panel entirely. If that's the case then the batteries wont get any more current until they drop to 3.94 volts (27.6/7). Isn't this exciting! :-)
Dacian's charge controllers are beautiful things and incredibly well designed from what I have seen. I'd love to get my hands on one but I think this is still a valid experiment in the mean time.
have you came back ? it was 2016, watching in 2018
What about the amps?
I'm sorry I don't understand the question?
Sorry for not making the question clear,
anyway what I meant was how the charge controller knows what current to charge the 18650s with...
You can adjust the voltage on the controller by selecting the battery type (AGM, flooded ect) but you can't control the amps being sent to the cells right? I thought the cells might not be able to accept all that current being put into them since most 18650s can only except 1.6A max.
I see - thanks for expanding. As we are dealing with solar there is no guarantees - I did talk about this is the video. The bulk phase will not be constant current. The solar panels I had connected to these 18650s could deliver a maximum of 2.86 amps in perfect conditions (so that is pretty rare) and as we're using a PWM controller it is likely that the panels will not reach their maximum power point. Also that theoretical maximum current is shared across all the seven cells. So in effect we are charging these cells pretty slowly and we're not going near their fully charged capacity. I've expanded this setup now to e 7s4p pack and left the same solar panels on the setup. So I'm charging these even slower now.
I guess you need to calculate the maximum charging rate you are comfortable with and connect the right sort of solar array (or panel) to suit.
Are the panels able to provide 2.86 amps, at 24v?
Doesn't that mean the cells will have the full (potentially. I use the 2/3rd rule, so realistically 2.86* 2/3rds=) 1.9 amps down through all the cells in series. IE., each cell will have 1.9 amps.
Now that you are using, a 4p, this will be 1.9/4, so just under half an amp. But there was the possibility before , for much higher current. Maybe I've made a mis-calculation in my thinking? I would value your input here, as I am looking at doing something similar, but having trouble understanding the charge controller options.
@@AdamWelchUK can I get ur email id please
I am building a pack with 26650's that have 3.5 AH per battery, so it will easily exceed a lead acid battery.
You don't float lithium-ion batteries. just turn off the charge when the current drops, and then restart when the batteries hit a particular lower voltage.
4s i better ?
12v solarpanel me cn3722 ceap laguvu to challge.
Charging Li Ion cells in series is dangerous since capcity of the cells is never exactly the same. If the cell with lowest capacity is full first >> the voltage on this cell will exceed 4,2V. The same applies for discharge. The cell with lowest capacity will exceed its lowest allowed voltage. Since the cell with lowest capacity gets over-stressed it will even more reduce its capacity and this negative effect to this weakest cell is going to happen earlier. Never ever charge Li Ion cells in series without charge control for each individual cell. Otherwise you could see spontaneous firework.
+Sven Georgi Have you watched the rest of the series? Spoiler alert though... one year on and no fire, no explosions.
You’re absolutely right there can be issues, but a well thought out system can run happily for years and the risks can be minimal.
woww very nice
uhm got a easier solution for you. use a portable solar panel like for instance a ALLPOWERS 100W Solar Charger together with for instance a nitecore d4 charger that can run on 12v dc connected to the 18v port via a step down converter.
when charging like i mentioned you'd obviously want to use the batteries in a battery holder like you see at 8:36 instead of making a pack out of them. Charging this way eliminates all troubles with properly charging each individual battery.
Show the specifications of positive and negative
A couple of weeks? You're cruel, Cruel I say!
+David T. Sorry! :-)
if you havent check electrodaus channel, he uses 8 cells in series to charge the cells directly off the panels! th-cam.com/video/1SVA5hAdmJ0/w-d-xo.html
no bms on liion is so wrong :w
ok
please made in
that was so dumb to have to go through so much trouble because you've already got a charge controller. Throw that thing in the trash and get you something that is programmable. Use a 4S pack and short charge it and ur batteries will live forever
I'm really interested to see how an off the shelf lead acid charger works with lithium. I've been running it a year now. The channel is mainly about cheap products and unfortunately the cheap lithium chargers (none programmable) seem to do a far worse job at charging lithium than the lead acid ones do.
If my lithium bank gets bigger (and there's a good chance it will) then a programmable solar charge controller will definitely be the way to go. You say dumb, I say interesting!
Cheers
Really enjoy it. Let's check Avasva plans also
the China no boss