If you're continuing to do these detailled tests and information, Will Prowse should be scared with a new TH-camr taking over ;) Keep up the good work!
@@OffGridGarageAustralia The reason Will Prowse gets higher capacity results is because he charges the batteries, allows them to rest, then does another bump charge to maximize absorption.
Excellent review, I have several sets running in 24v on offgrid inverters powering my house as I do not trust governement power supply anymore. Greetings from Belgium
Thank you Andy. A fantastic test. The joy is great about your positive engachmang and brilliant mood. As another here on the channel said "not many youtubers one can bear to comment on but your videos just have to be commented on the basis of your positive engagemang" ceep up the good work 🙏 I can't wait for the continuation 🤩
Very much enjoyed your videos. It might be interesting to log temperature rise of the cell as well. One of the problems with having lithium batteries in Brisbane is that the ambient temperature can have a larger affect on cell life than the cycles. I've been considering a cheap air conditioning system to keep the ambient temperature around the cells well under 30 degrees - very little energy required, solar driven.
I was really hoping for better. I'm buying, testing, and reselling on ebay here in America. The 100ah cells I test usually make 107-110ah. At least they made 280 though.
I agree, especially that the rating on the technical specifications for the battery claims 280Ah @ 1C The test performed here was less than .1C and barely got to 278Ah...something is not right 🙁
The interesting thing should be to test this cell at 1C, it means, if I am not wrong, drawing 280A for one hour and see if you will get 280AH at the end of the test? During the test you performed, you have got almost 280Ah at a rate of 22-23 Ah, that it corresponds to only 0.08C. Thank you for your job.
Considering you were less than an Ah off rated capacity and that meters voltage rating is already showing as off compared to the multimeter, I can say that cell is probably a winner, and may have read over 280Ah on a professional instrument. An instrument that probably costs $1000's. So the deviation of the little fan cooled tester is acceptable, considering they cost less than $100 :)
Capacity measured plus the calculated losses of the wire harness >280Ah It would be interesting to cycle this same cell 50-100 days in your solar power set up, then pull it out and repeat the same test set up you just did, as it is known that brand new cells will test higher initially but no one ever seems to state how much higher. Seems like these ones are "a winner". Great vid Andy.
Although I never did a full drop to min cell voltage of 2.5v for a cell, my 4s 12.8v configuration I was able to draw 262.6ah at a constant 46amps via a inverter running a pond pump with the lowest cell voltage at 2.986v and highest at 3.124v with total cells at 12.2v and SOC 6% via my Daly 150a BMS and VictronConnect 712 smart. Duration from max charge was 5hrs 48mins.
I believe that resistance is what resistance the device is at to get the amps you need the math seems to work out and you should be able to set the current to like 1A and it should be the same as the voltage
You have wires resistance so the internal resistance will not match you cell. I have the same electronics load tester. Great video. Looking forward to the next test.
Hi Andy, nice one! Looking forward to the next tests :-) Could you put in the shunt between the electronic Load tester and the battery next time? So we all could see the difference between the el. load and the shunt
You need a lot more subscribers, i never comment on videos and i limit myself to leave a like but i really enjoy your content good job. Even if i have seen all videos on TH-cam about the subject i still enjoy watching you talking about the same things.
Very nice! I would consider that Full capacity for the cell. Looks like you spent your money wisely and those cells will last for many, many years with proper care. Best of luck and I'm looking forward to the next video.
022721/0504 PST- Brisbane 2304h Those two cell capacity testers are quite unreliable and notorious. For a set up like yours what you need is pure digital cell capacity tester manufactured by EAST TESTER (China) Model ET-5410@40A discharge current. Item available with Alibaba. US$175 AU$227. I found it extremely good and very relatable in test results. The settings are a wee bit complicated but once mastered the procedure, it’s easy to work on. Discharge test result per one 280Ah cell @ 40A = 5 hours. Best wishes and 73s...
There is a DC receptable right next to the dummy load terminals which should be there to power the tester independently of tested power source so it won't drop out prematurely due to the low voltage. At least my tester has this feature, not the same model in the vid.
It doesn't so much matter if they are accurate, as long as it's repeatable, after testing 1000's of cells, I learned to compare testers, to confirm they are equal, so the numbers are repeated by both, it doesn't have to be perfect, but it helps..
The no name DMMs are for high school kids, who have limited cash flow. FLUKE INSTRUMENTS. These are standard DMM for DIY people and also used in Nuclear facilities. Prices vary according to requirements and Models. These instruments can be calibrated at authorized stores, by trained technicians. Get 2, even used ones, and get it calibrated. You’d be happy to possess these fine instruments. 73s...
@@sreekumarUSA I haven't found a reason in Solar that I need to be that accurate to spend 5 times the cost for a Fluke and I don't need to be exactly right all the time just close enough to be safe.
I would be interested to see the difference if you test both cells with both testers and show how big the difference is between them and if you get the same result you can test two cells at the same time
Nice test! And good job measuring the voltage drop over the cables. That drop shows some resistance which the tester is attributing to battery internal resistance.
Great video, I also find it fascinating to watch the numbers :D. Also the amount of current drawn from the battery is not necessarily related to its voltage, especially in a case where a load is drawn through a constant current/constant voltage device (like some types of inverters), drawing more amps as voltage decreases to maintain a wattage output. I am interested to hear what you plan to do with these cells!
Greetings Andy from Upper Coomera, thanks for making such great videos, about an hour ago I have just placed an order for 8 3.2v CATL271 cells, now the long wait begins, but ordering using Alibaba was so easy.
You have now 16 batteries good working for free. Well done Andy! I want do the same only I don't know how to start with 100Ah or 120Ah? 280Ah is too big for my 2kwp solar.
Bigger is better as it means it's a lower c-charge rating. Eg 2000w solar charging a 2000wh battery is 1C charge (bit fast), where as 2000w charging a 8000w battery is 0.25C charging which is better for the batteries. Hope this helps.
As mentioned elsewhere, that 140mOhm figure is the equivalent resistance of your tester load, not the battery. Surprised that the tester is not a FOUR WIRE instrument - two wires to measure current (as you have now) and a further light-duty two wires on their own croc clips which you connect directly to the battery terminals, to measure voltage at the battery itself. This eliminates lead resistance in the current path altogether (or at least, it correctly takes it into account as effectively part of the load). The usb sockets on the tester board suggests it can probably output data to a PC, to log voltage drop and Ah in real time, to save you the bother of watching :)
Thanks, I've got a second tester which has the voltage sense directly at the battery terminals. Really? That's the load resistance, not the battery internal resistance? I thought it says that in the manual...
@@OffGridGarageAustralia yes, that's definitely the load resistance. There are other meters that have readings for both internal and external resistance though.
Do those Chinese battery testers need to be powered separately? From what I can see, you are powering the tester from the source, there's USB ports on there! Could they be for powering the tester? I have a funny feeling that I have seen someone else on TH-cam use one and possibly powered it with a different source, it's possible that the voltage display is inaccurate because you have it set up the way that you have! Might be worthwhile looking into!
Ridiculous question, Andy! If you used a sized matched copper ring terminal & a single, hydraulicly pressed, air-tight seal at each junction with a 2 AWG equally sized cable- would you have reduced the 'line loss' of 0.007 & 0.0073 millivolts? It's so small, it's meaningless, but- as I build a system, I could lose lots of Watts over relatively short distances... It's a thinking ahead question, but- annoyingly smaller in the larger test!!! Congratulations, it must make you much happier to know that you got what you paid for!!!
Thanks David. The better your crimping job is, the better the connection and lower the losses. I didn't pay too much attention to mine as it is just for the test. For the actual system, I will buy an hydraulic crimper though.
Jeez, I just commented with the same idea on the previous video! My line of thought is how well that works with the positive battery terminal in (fuel-powered) vehicles.
@@DCGULL01 I love the brain-storming! I also suggested drilling a small hole in each busbar to mount BMS wires. That's what I'll be doing if I decide to go with busbars. That should make the terminals more stable, easier to service, and easier to isolate voltage drops.
Word of warning, I have bought multiple of those 180w capacity testers and they ALL fail within a short period of time. When (not if) they fail, they fail in a short circuit making tons of smoke all over the place. Highly recommend an inline fuse of some sort before connecting any further loads.
@@jjthegreat1981 on thanks very much for that info. I've planned to test the 48V system with it to. Have you got the tester with the green board or the red/brown board?
I saw a company makes upto 1kah cells, rated to discharge 1c, they have 6 terminals, 3pos, 3neg, that's insane, but I'd like about 8 of them! Maybe 12! I would NOT want to test that monster! They are the calb cells, I just wonder the cost! Only thing, if one cell dies, you are powerless, I'd rather have atleast a couple cells paralled, so possible only half power is lost, I'd like to get about 42 of the cells you have eventually, mine are basically new now, so there is much life remaining, maybe in a few years, or if my power needs grow, Merry Christmas! PS. Maybe you can check out the 1000ah cells, and do a video on them??
Thank You for opening this old mans eyes. I have been watching you for a while. I have Four 280Ah batteries Lithium Iron Phosphate batteries I am waiting on and because of you today, I order Two more so I'll have six. Why? I'm Old. I have been setting here thinking I'll hook them in Parallel like my acid ones and this will give me 1,120 Amp Hours, Boy Was I wrong. I guess I need to connect them in Series for a 12 volt system and a full 480Ahs. I live in my fifth wheel so 480 Ahs will not be enough. Tell me if I'm wrong, but I guess I'll have to connect in Series and then the last two in Parallel for a few more Amp Hours, Correct? Thank You Rick
Hi Rick, Thanks for your comment. 6 cells will not work for a 12V setup! You need either 4 or 8. If you have 4 you just connect them in series for a 12V system like: -⬛+ -⬛+ -⬛+ -⬛+ If you have 8 you need to parallel every two cells first like ┌ -⬛+┐ - ┤ ├ + └ -⬛+┘ and then have this pair in series with the other 3 pairs ┌ -⬛+┐┌ -⬛+┐┌ -⬛+┐┌ -⬛+┐ - ┤ ├┤ ├┤ ├┤ ├ + └ -⬛+┘└ -⬛+┘└ -⬛+┘└ -⬛+┘ Does this make sense?
@@OffGridGarageAustralia The picture you show confuses me, Sorry. Maybe you could do a short video for myself and possibly others here. Sorry I'm so troublesome. I do live in my fifth wheel and everything I have is 12 volt or 110 volt. I use solar and a wind turbine to keep my 4 lead acid batteries charged, but they are getting old, Like Me! So you're saying I need to cancel the order for (2) more Identical Batteries and Order four (4) more Identical Batteries. Same brand name is important or not. Thank You for your time and trouble and for responding so quickly.
Yea, Rick, you can only use 4 or 8 batteries for a 12V system. The video you linked above shows the setup as I described it in my first reply. parallel 2 batteries and do this 4 times. You will have 4 pairs with 2 batteries each. The put these pairs in series to achieve the 12V. Video will follow soon...
Recently I did similar tests on my 150 Ah cells. On an individual basis the cells were fine, however, when connected two in parallel and then four of these parallel groups to make a 12 volt battery, I lost 25 - 30% of the capacity. I tried it several times moving batteries to various positions and got the same results. So I decided that the complex internal chemistry and internal resistance of the batteries caused some to drain more rapidly than others just as if you take different value resistors and put them in parallel the current through each will not be identical. Since it is the current that drains or charges a given cell it makes sense variations in internal resistance will cause variations in individual cell resistance and currents. Just as with parallel resistors, the voltage across resistors will be the same but the currents are different and I think the cell being taxed pulls down the voltage for the parallel set. Also, although my cells were fine as individuals and exhibited small cell differential voltages for most of the test of less than 10 mv (at the very end it got up to 30 mv) when connected in parallel I saw differential voltages of up to 300 millivolts. It would be very interesting to see if you could repeat my experience on your cells. For now I have concluded that if one wants a larger capacity battery than the value of the cells they own they should make single batteries of cells in series and then connect the batteries at the battery level in parallel with each battery getting its own BMS. Otherwise, based on my experience, you will lose a lot of capacity.
@@ursodermatt8809 This excellent research paper provides evidence for my conclusion and sheds a lot of light on the subject: www.sciencedirect.com/science/article/pii/S0378775316309995
@@ursodermatt8809 Actually Tesla and everyone else does have this problem. A special BMS can be designed to deal with it or batteries can be carefully qualified to minimize the problem. Also, as you mention, Tesla parallels many, many cells. The loss of capacity from a bad cell is inversely proportional to the number in parallel. So a bad cell in Tesla's highly paralyzed case may be barely noticeable. I am sure Tesla handles it one way or another. However, in my case, I have just found found a bug in my Chargery BMS firmware that miscalculates the amp hours used by at elast 16%. Vendor told me to update to just released version of software that was supposed to fix the problem but just tested it today and it is not fixed. Still though, I don't think this explains everything I observed. I am guessing that I have a weak cell as well but it is hard to identify a bad cell in a parallel system because the good parallel cells makes the group voltage look okay. Or possibly the way I paralleled my batteries also may have contributed to the issue. But, in any case, turns out there are problems with paralleling batteries that in bad cases (mostly bad luck or ignorance) with some batteries can cause fire if not handled by a special BMS. I don't know if you read the research article I linked earlier but it also illuminates some aspects of the problem. In addition, Orion makes an expensive BMS and they have a lengthy discussion of the parallel configuration issues here: www.orionbms.com/manuals/pdf/parallel_strings.pdf This is right out of the Orion article: "In the event that one of the cells develops a reduced capacity or high resistance (as is typical for aged or failed cells), the stronger cell will take more of the load and essentially prop up the weaker cell. In that event, the BMS is able to see a decrease in the overall capacity or an overall increase in resistance. With two cells paralleled together, a single weak cell can affect the resistance up to 50% and the capacity up to 50%. If three cells are paralleled, a single bad cell can affect the resistance and capacity of the total paralleled block up to 33% (with four cells paralleled, up to 25%, and so forth). As more cells are paralleled, a single failure becomes more difficult to detect, but redundancy is also increased since a single cell failure will have less of an impact on the overall performance of the battery. Cells directly paralleled with each other will automatically balance each other since they are permanently connected." As to your comments, the reason you lose a lot of capacity is not just because of current flow through internal resistance and eddy currents. The main problem is that the energy becomes unavailable because the parallel combination with an unhealthy or significantly different cell drops voltage quicker than it should and the BMS trips prematurely. Batteries are full of distributed resistance and energy such that you can actually have different voltages at different locations throughout the cell simultaneously. That is why when you stop charging or discharging the voltage you observe at the terminals will not be the same a few minutes or hours later. The charge in the depth of the battery actually needs time to migrate to the terminals. It all depends on a lot of variables. So a bad cell can pull down or up a good cell at the terminals and trip the BMS. Then, give it some time and the balance will work itself out again. A battery is not only modeled with a voltage source in series with a resistance, but also with another parallel string of a resistor and a capacitor. And, I suspect, it you really did it right, it would be modeled with a great many internal resistance and capacitance paths. I am not sure what you are saying with your 500 ah battery and 10 ah battery example. If you put them in parallel at the same voltage they will probably sit fine but as soon as you charge or discharge them the 10ah battery is going to clobber your capacity and trip your BMS and/or melt. No way it can handle the current unless your load is trivial. You will have multiple problems such as mismatched capacity, mismatched internal resistance, etc. Frankly, most people are just not aware of the issue because it is not widely discussed and most people don't really accurately and precisely test the capacity of large battery banks. Also, when they do test it is usually when the batteries are new and, thus, less likely to show a significant problem. It is also a hard problem to work around (as in expensive). Maybe they test one or two individual batteries or a few in series but often not much more. Folks settle for what they get and, given the complexity of the issue, that is not a bad choice. There are many versions of this problem depending on configuration. Let me give you one weird case example that can happen. Say you parallel at the battery level (not the cell level) and you, for instance, have two 4s batteries paralleled together. Let's say one of these batteries is in good shape with matched cells but the other has a bad cell. Further, assume each battery has its own BMS and that each BMS has a separate relay or Mosfet to control charging and discharging. So you would have a path for charging and a relay for it and a separate relay and path for discharging on each battery but the charging paths connect together at some point as do the discharging paths Okay, given the above, you go to charge your batteries and the good battery goes all the way to 14.6 volts while the bad battery has a bad cell that causes it to have lower capacity and it trips the charging relay when one of its cells reaches 3.65 volts and the other cells are at 3.3 volts. Okay, the charging relay for one battery trips early and the charging relay for the other trips at 14.6 volts. Seems good right? But it is not because the discharge relays also create a path to each battery and on creating a parallel path between the batteries the battery at 14.6 volts becomes a charger for the battery at a lessor charge. Since one of the cells in the bad battery is at 3.65 volts it is now going to overcharge as the higher voltage battery transfers charge into the bad battery. If the voltage mismatch is big enough you could even have a melt down. Play with the voltages and number of bad cells in this configuration and you can see that you could have a battery overcharging a cell to more than the 4.2 volt never never land. Even if you do not have the problem now, you might as batteries age. I know that the example above is not the config used in the video but if you read the Orion article it discusses the issues with many different parallel configurations including some similar to that used in the video. Point is, it is more complex and interesting than most folks are aware of but I don't know just how big of a problem it truly is. If one does not notice a dramatic event like a big loss in capacity of a meltdown the issue may never be found or accounted to battery aging. I'd sure like to see the capacity of the batteries used in the video actually tested both in series and in parallel. It may be that it will work out fine because the batteries are matched and/or my BMS problem over-exaggerated the issue and/or busbars between every terminal of the parallel groups cuts the issue. But I sure would like to see the tests by multiple people and various configurations so we could get a better feel for the situation. The issue does exist but I suspect it causes a capacity loss that few actually know about (or maybe care about). By the way, you need to use multiple instruments to monitor amp hours, Watt hours, voltages and currents because I use 3 simultaneously and they all give different answers (which is how I found my BMS firmware problem - two were close, my manual calc. was close and the BMS was far off). In the end, I will probably build my own test instruments because I actually have a degree in Electrical Engineering (although that was a long, long time ago).
Thsnks for this video I'm about to do the same exact thing with a diy 18650 battery and this video just saved me from making an error. Just curious, while you're learning all of this stuff, who/what are your main sources?
This is a great series. I’ll be building a battery for my camper soon. I’ve never used Alibaba. These batteries seem to deliver as promised, why did you choose this battery and this vendor?
This was the only vendor which offered 5 years warranty on the cells and also was with Alibaba for over 8 years. I have found cheaper sellers but went with them and so far, so good!
Next time you order batteries, order 2~3 battery testers extra. They tend to die out after some use, better to have backups than to be left stranded in the middle of a test.
Hey Andy, looks like you're on a winner with these batteries, so with 16 that give you around 13kWh (probably 10kWh usable) That's a "Normal" days driving in the Teslander ?? I'm still battling with my Outlander PHEV, but am looking at the MG PHEV when it arrives in Australia, hopefully Q1 next year. Merry Xmas mate, happy testing !! Andy :)
Go full EV. I know two people with the MG ZS EV. Battery pack will give me 14.5kWh of which I can utilise 100%. I use only 4-6kWh for the Teslander per day for my commuting, so that's definitely a green light for this project.
Please ask the supplier 16 with delivery to Macedonia what is the price.Dont have experience with Alibaba.Ty in advance and god bless you.You are great keep up the videos ☺️☺️😉😉😉
Thanks so much this was very educational and also very encouraging to see that these batteries which are probablly the best value you will find anywhere online (believe me, I've LOOKED). I have a question though, why can you not leave these batteries fully charged for too long, what would happen and how long would it take before there would be an issue? Is it safe to leave a battery at 90% capacity?
Thanks for your comment and feedback. Due to chemical reactions, the battery will lose capacity when charged to 100% and kept at this stage. This will shorten the life if you do this to often. You can charge to 100% of you are discharging it right away again. The chemicals inside are most stable at 50% state of charge (SoC). Everything below or above will shorten its life. 90% is far better than 100%, 80% is even better. If you want to store your battery for a long time charge it to 50-60%. For general use, you can use it from 10-90%, better from 20-80%. If you want the battery to last a really loooong time charge from 30-70% only.
@@OffGridGarageAustralia Thanks for the response! Ok wow that's really something I had no idea about. It makes me wonder what the manufacturer's mean when they say the battery is good for 3,500 cycles. Are the assuming when they give this number that the battery will be each day discharged and charged to 90% capacity or is the 3,500 cycles the really best case scenario of only using the battery in the 30 - 70% range? Sorry for the questions but your a wealth of information and i'd be kicking myself if I did not ask.
@@bethechangeme2233 so, the specs say if you do depth of discharge (DoD) between 10-90% you will get 3500 cycles. If you do 30-70% DoD is more like 10.000+ cycles. Batteries in satellites do only 40-70% so they last 25 years reliably.
@@OffGridGarageAustralia it would seem that one would need to triple the required size of their battery bank to stay within the DOD of 30-70% in order to make them last the 25 years yet if the DOD is between 10 and 90% that same three battery banks would last 27 years! Would it be safe to say forget about compressing, forget about super tight DOD's just go for the 10% - 90% and in 9 - 10 years we will have better technology?
Those little energy meters NEED to be calibrated. Their tempco isn't very good so the only way to get reasonable results is calibrating beforehand. I think most of them want 20V 1A as the standard. Some do allow you to use a known voltage and match but I don't think that's one of them.
I ordered batteries on your recommendation and they came in garbage.I thought I found a solid supplier but so far this is the worst quality I have bought:)
Interesting! You took a pretty rough procedure with 0,79C with high environmental temperatures. Data sheet says 0.5C and 25 celsius and I remember (didn't memorize the source) that after activaton you need a bunch of complete cycles to reach full capacity. Discharging with 1C will reduce the capacity at 3% and high temperatures (data sheet mentions 55 celsius) can reduce with another 5%. So I assume the capacity will exceed 280 under ideal conditions. Sounds good to me. Would be nice to reproduce the same test more times of the same cell for verification (etwas Deutsche Gründlichkeit kann nicht schaden ;-) ) Funfact for me was the changes between the different releases of the data sheet (mine: www.lithium-powerstore.de/media/products/akku/datenblaetter/eve/akku_eve_LF280.pdf - May 25th, 2018 )
They still make those they're called tubular plate lead acid they have about a 20-year life expectancy pretty expensive and heavy You can purchase them in a 3,000 amp hour 2 volt each cell
Try those: www.aliexpress.com/item/1005001715950047.html They have free shipping to Europe and seem to be tax free. They're way too cheap but hey - nothing ventured, nothing gained... 😉
Fantastic result on capacity Andy. Thanks for sharing that. Looking forward to the discussion on compressing batteries of this type. One commenter noted that the readout on the load was showing the internal resistance of the tester. I think that's right. 3.2V / 23A = 0.139 Ohms. The voltage drop from terminal to terminal of 0.14V (combined)
6:36 that's the external resistance, not the internal resistance of the cell. That other tester does show a measurement of the internal battery resistance, and it's done by using the difference between the battery voltage with no load and the voltage under load, and divides that delta by the load current. I did that separately and the meter readout for internal resistance seemed reasonably close. The no load voltage is based on your configuration setup of the meter for 100% SOC, so you have to do that right before that test. The battery label showed 0.15 milliohms for internal resistance, which has nothing to do with the hundred plus milliohms of the 0.139Ω external resistance that the load meter measured.
The resistance measure 0.14Ohms and the effective resistance the battery is discharging over. 3.24V/23.1A=0.14Ohms. its not the internal resistance of the battery..
If the lights are not flickering, it is just a camera issue. Take your phone and look through the camera at a tv, computer screen. You will see weird flickering, because the cameras are slower at picking up the lights. Not a problem either ways. If the shed was running on solar and a cloud came on top, voltage dropped, would cause the bulb to flicker as well if connected directly.
More like 5 hours. Your inverter will only be 85-90% efficient. Plus losses in cables. Plus 5ah at 110v is more like 550w. Recon you only want to be using 80% of these lifepo4 batteries to maximise life cycles, so don't drop bottom 10% or charge over 90%. Will increase your life cycles from 800 to 1000's :)
@@w3bb0y luckily the devil is in details . the room to b cooled is 1/4 the cubic ft these window units are rated for . previous attempts with agm 500 ah have only used 40% d.o.d. on 8hr runs so I'll b giving the 280s i try in summer . should b interesting .
The cells are great for 20-30a applications. Could you share with us a picture of the QR code on the cells. Is it QR code 02YCB66710000J ?. I noted your Alibaba links does not state it is EVE cells. I think it is EVE copy cat cells, but thats fine. The sellers only state in the private comments that it is EVE cells. Real EVE cells can deliver 1C
Since you're working with such low voltages and you have to be accurate down into the millivolt range do yourself a favor dump the cheap Chinese meters. Get yourself a fluke 87v or 289. You will never have to worry about whether what you're reading is correct. It will be. you can bet your life on it and many professional electricians and technicians do everyday. Also if you can find a good Weston cell you can check the calibration of the meters. These can be a bit fiddly as you have to keep them at a known temperature to ensure the calibration is correct. you also cannot move them or you must let them sit in place for a day or two for the chemicals to settle back out. If you must use the Chinese meters at least get a known voltage reference that is calibrated and is referenced back to a known accurate source. One item is known as a DMM check source. These are available at dmmcheckplus.com. They're not $20.00 but they're also not expensive and would be very helpful to verify your equipment accuracy. A basic unit is $123 and will give you a precision 5 volt AC and DC source plus a current source and a resistance standard. For an additional $20 you can get a capacitance reference source. And there is an optional case if you would like it. Also the manufacturer offers a low-cost recalibration for 20 bucks. This is one of the best deals in calibrators that are built and tested out there.
Acurate dummy load ....Aliexpres....13$ "9.99A 60W 30V Constant Current Electronic Load Discharge Battery Tester" Is best there is ....SKY RC MC3000 calibrated.....Is as reference....also have 4 wire voltage measuring....
If you're continuing to do these detailled tests and information, Will Prowse should be scared with a new TH-camr taking over ;) Keep up the good work!
He will always be the best!
But thank you for such kind words 🙏
@@OffGridGarageAustralia The reason Will Prowse gets higher capacity results is because he charges the batteries, allows them to rest, then does another bump charge to maximize absorption.
Excellent review, I have several sets running in 24v on offgrid inverters powering my house as I do not trust governement power supply anymore. Greetings from Belgium
Thank you Andy.
A fantastic test.
The joy is great about your positive engachmang and brilliant mood. As another here on the channel said "not many youtubers one can bear to comment on but your videos just have to be commented on the basis of your positive engagemang"
ceep up the good work 🙏
I can't wait for the continuation 🤩
Very much enjoyed your videos.
It might be interesting to log temperature rise of the cell as well.
One of the problems with having lithium batteries in Brisbane is that the ambient temperature can have a larger affect on cell life than the cycles. I've been considering a cheap air conditioning system to keep the ambient temperature around the cells well under 30 degrees - very little energy required, solar driven.
I was really hoping for better. I'm buying, testing, and reselling on ebay here in America. The 100ah cells I test usually make 107-110ah. At least they made 280 though.
I agree, especially that the rating on the technical specifications for the battery claims 280Ah @ 1C
The test performed here was less than .1C and barely got to 278Ah...something is not right 🙁
@@georgedemean2228 he probably actually got the 277ah version because everywhere I look in China they are out of stock for 280ah version.
@@JM-yx1lm At .1C discharge test he should have had no trouble getting 290-300 Ah out of the cell
The interesting thing should be to test this cell at 1C, it means, if I am not wrong, drawing 280A for one hour and see if you will get 280AH at the end of the test?
During the test you performed, you have got almost 280Ah at a rate of 22-23 Ah, that it corresponds to only 0.08C.
Thank you for your job.
That is absolutely correct. The specs of the cell stating 1C/0.5C discharge. I've made a video about this already and will publish it very soon.
Brilliant! This is the video I was waiting for.
Hehehe, me too!
Considering you were less than an Ah off rated capacity and that meters voltage rating is already showing as off compared to the multimeter, I can say that cell is probably a winner, and may have read over 280Ah on a professional instrument. An instrument that probably costs $1000's. So the deviation of the little fan cooled tester is acceptable, considering they cost less than $100 :)
Capacity measured plus the calculated losses of the wire harness >280Ah
It would be interesting to cycle this same cell 50-100 days in your solar power set up, then pull it out and repeat the same test set up you just did, as it is known that brand new cells will test higher initially but no one ever seems to state how much higher. Seems like these ones are "a winner". Great vid Andy.
Although I never did a full drop to min cell voltage of 2.5v for a cell, my 4s 12.8v configuration I was able to draw 262.6ah at a constant 46amps via a inverter running a pond pump with the lowest cell voltage at 2.986v and highest at 3.124v with total cells at 12.2v and SOC 6% via my Daly 150a BMS and VictronConnect 712 smart. Duration from max charge was 5hrs 48mins.
That's a great result.
I believe that resistance is what resistance the device is at to get the amps you need the math seems to work out and you should be able to set the current to like 1A and it should be the same as the voltage
You have wires resistance so the internal resistance will not match you cell. I have the same electronics load tester. Great video. Looking forward to the next test.
Ah, yes, of course. The tester sees the wires and connections as well... Thanks for that!
Hi Andy, nice one!
Looking forward to the next tests :-)
Could you put in the shunt between the electronic Load tester and the battery next time?
So we all could see the difference between the el. load and the shunt
You need a lot more subscribers, i never comment on videos and i limit myself to leave a like but i really enjoy your content good job.
Even if i have seen all videos on TH-cam about the subject i still enjoy watching you talking about the same things.
Very nice! I would consider that Full capacity for the cell. Looks like you spent your money wisely and those cells will last for many, many years with proper care. Best of luck and I'm looking forward to the next video.
Great test setup and your results really look reliable.
Greetings from Germany 👍
Hallo in die alte Heimat!
The lights is blinking in the footage. I think either the 50/60HZ or the ISO should be adjusted in your camera if I'm not wrong.
022721/0504 PST- Brisbane 2304h Those two cell capacity testers are quite unreliable and notorious.
For a set up like yours what you need is pure digital cell capacity tester manufactured by EAST TESTER (China)
Model ET-5410@40A discharge current. Item available with Alibaba. US$175 AU$227. I found it extremely good and very relatable in test results. The settings are a wee bit complicated but once mastered the procedure, it’s easy to work on. Discharge test result per one 280Ah cell @ 40A = 5 hours. Best wishes and 73s...
There is a DC receptable right next to the dummy load terminals which should be there to power the tester independently of tested power source so it won't drop out prematurely due to the low voltage. At least my tester has this feature, not the same model in the vid.
Yeah, I did connect mine to the external power supply as the test voltage was under 8V.
It doesn't so much matter if they are accurate, as long as it's repeatable, after testing 1000's of cells, I learned to compare testers, to confirm they are equal, so the numbers are repeated by both, it doesn't have to be perfect, but it helps..
The ohms on your tester is the LOAD resistance, not the internal battery resistance. Just divide Volts and Amps.
Great job on the test!
Thank you!
The voltage difference between instruments is very common and something we just live with.
The no name DMMs are for high school kids, who have limited cash flow.
FLUKE INSTRUMENTS. These are standard DMM for DIY people and also used in Nuclear facilities. Prices vary according to requirements and Models. These instruments can be calibrated at authorized stores, by trained technicians. Get 2, even used ones, and get it calibrated. You’d be happy to possess these fine instruments. 73s...
@@sreekumarUSA I haven't found a reason in Solar that I need to be that accurate to spend 5 times the cost for a Fluke and I don't need to be exactly right all the time just close enough to be safe.
I just subscribed. Made a order for these cells and need to learn all I can!! Thanks
I would be interested to see the difference if you test both cells with both testers and show how big the difference is between them and if you get the same result you can test two cells at the same time
Nice test! And good job measuring the voltage drop over the cables. That drop shows some resistance which the tester is attributing to battery internal resistance.
Great test! I think if you would have lowered the amperage at the end to like 5A, you could have gotten even more out of that battery.
That electronic load shows the impedance of the electronic load, not th einternal impedance of the Cell under test.
Yes, Volts divided by resistance = current.
Yea i think the capacity tester voltage differs from your multimeter at the battery terminals because of that 7mV voltage drop across the cables
Thanks alooooot and have a nice day!!
From Montseny Catalonia, excelent work, you are trespasing frontiers
Great video, I also find it fascinating to watch the numbers :D. Also the amount of current drawn from the battery is not necessarily related to its voltage, especially in a case where a load is drawn through a constant current/constant voltage device (like some types of inverters), drawing more amps as voltage decreases to maintain a wattage output. I am interested to hear what you plan to do with these cells!
Thanks for your feedback. You absolutely correct.
You may want to watch the very first video on my channel. This explains the project.
Greetings Andy from Upper Coomera, thanks for making such great videos, about an hour ago I have just placed an order for 8 3.2v CATL271 cells, now the long wait begins, but ordering using Alibaba was so easy.
Sir how was price per cell.
@@diy-fun509 price was approx the same as xuba battery and am looking forward to receiving and checking them
You have now 16 batteries good working for free. Well done Andy! I want do the same only I don't know how to start with 100Ah or 120Ah?
280Ah is too big for my 2kwp solar.
Ali Express has 100 Ah cells and 90 Ah they may both be the same but for like $160 for 4 cells
More Ah is better.
280Ah is perfect
Bigger is better as it means it's a lower c-charge rating. Eg 2000w solar charging a 2000wh battery is 1C charge (bit fast), where as 2000w charging a 8000w battery is 0.25C charging which is better for the batteries. Hope this helps.
@@w3bb0y right. I agree 100%
As mentioned elsewhere, that 140mOhm figure is the equivalent resistance of your tester load, not the battery. Surprised that the tester is not a FOUR WIRE instrument - two wires to measure current (as you have now) and a further light-duty two wires on their own croc clips which you connect directly to the battery terminals, to measure voltage at the battery itself. This eliminates lead resistance in the current path altogether (or at least, it correctly takes it into account as effectively part of the load).
The usb sockets on the tester board suggests it can probably output data to a PC, to log voltage drop and Ah in real time, to save you the bother of watching :)
Thanks, I've got a second tester which has the voltage sense directly at the battery terminals.
Really? That's the load resistance, not the battery internal resistance? I thought it says that in the manual...
@@OffGridGarageAustralia yes, that's definitely the load resistance. There are other meters that have readings for both internal and external resistance though.
Do those Chinese battery testers need to be powered separately? From what I can see, you are powering the tester from the source, there's USB ports on there! Could they be for powering the tester? I have a funny feeling that I have seen someone else on TH-cam use one and possibly powered it with a different source, it's possible that the voltage display is inaccurate because you have it set up the way that you have!
Might be worthwhile looking into!
GREAT RESULTS!!!
Ridiculous question, Andy! If you used a sized matched copper ring terminal & a single, hydraulicly pressed, air-tight seal at each junction with a 2 AWG equally sized cable- would you have reduced the 'line loss' of 0.007 & 0.0073 millivolts? It's so small, it's meaningless, but- as I build a system, I could lose lots of Watts over relatively short distances... It's a thinking ahead question, but- annoyingly smaller in the larger test!!! Congratulations, it must make you much happier to know that you got what you paid for!!!
Thanks David. The better your crimping job is, the better the connection and lower the losses. I didn't pay too much attention to mine as it is just for the test. For the actual system, I will buy an hydraulic crimper though.
Jeez, I just commented with the same idea on the previous video! My line of thought is how well that works with the positive battery terminal in (fuel-powered) vehicles.
@@charlesrichards5389 I think it was all about timing- we (Andy) were 'building it' at the time, and- lots of focus by the watching community...
@@DCGULL01 I love the brain-storming! I also suggested drilling a small hole in each busbar to mount BMS wires. That's what I'll be doing if I decide to go with busbars. That should make the terminals more stable, easier to service, and easier to isolate voltage drops.
Word of warning, I have bought multiple of those 180w capacity testers and they ALL fail within a short period of time. When (not if) they fail, they fail in a short circuit making tons of smoke all over the place. Highly recommend an inline fuse of some sort before connecting any further loads.
Thanks for the feedback. That's good to know. Was this all with higher loads? So far I have only tested single cells with 3.3V, so pulled 75W max.
@@OffGridGarageAustralia to be fair, I did run higher voltages. Testing 48v batteries @ 100 watts smoked them after a few hours.
@@jjthegreat1981 on thanks very much for that info. I've planned to test the 48V system with it to. Have you got the tester with the green board or the red/brown board?
I saw a company makes upto 1kah cells, rated to discharge 1c, they have 6 terminals, 3pos, 3neg, that's insane, but I'd like about 8 of them! Maybe 12! I would NOT want to test that monster! They are the calb cells, I just wonder the cost! Only thing, if one cell dies, you are powerless, I'd rather have atleast a couple cells paralled, so possible only half power is lost, I'd like to get about 42 of the cells you have eventually, mine are basically new now, so there is much life remaining, maybe in a few years, or if my power needs grow,
Merry Christmas!
PS. Maybe you can check out the 1000ah cells, and do a video on them??
Thank You for opening this old mans eyes.
I have been watching you for a while.
I have Four 280Ah batteries Lithium Iron Phosphate batteries I am waiting on and because of you today, I order Two more so I'll have six.
Why?
I'm Old. I have been setting here thinking I'll hook them in Parallel like my acid ones and this will give me 1,120 Amp Hours, Boy Was I wrong.
I guess I need to connect them in Series for a 12 volt system and a full 480Ahs.
I live in my fifth wheel so 480 Ahs will not be enough.
Tell me if I'm wrong, but I guess I'll have to connect in Series and then the last two in Parallel for a few more Amp Hours, Correct?
Thank You Rick
Hi Rick, Thanks for your comment.
6 cells will not work for a 12V setup! You need either 4 or 8.
If you have 4 you just connect them in series for a 12V system like:
-⬛+ -⬛+ -⬛+ -⬛+
If you have 8 you need to parallel every two cells first like
┌ -⬛+┐
- ┤ ├ +
└ -⬛+┘
and then have this pair in series with the other 3 pairs
┌ -⬛+┐┌ -⬛+┐┌ -⬛+┐┌ -⬛+┐
- ┤ ├┤ ├┤ ├┤ ├ +
└ -⬛+┘└ -⬛+┘└ -⬛+┘└ -⬛+┘
Does this make sense?
@@OffGridGarageAustralia OK, I'm old so I guess I'm wrong as usual and very slow.
I watched th-cam.com/video/zStEtH9Le-w/w-d-xo.html
Thank You
@@OffGridGarageAustralia The picture you show confuses me, Sorry.
Maybe you could do a short video for myself and possibly others here.
Sorry I'm so troublesome.
I do live in my fifth wheel and everything I have is 12 volt or 110 volt.
I use solar and a wind turbine to keep my 4 lead acid batteries charged, but they are getting old, Like Me!
So you're saying I need to cancel the order for (2) more Identical Batteries and Order four (4) more Identical Batteries.
Same brand name is important or not.
Thank You for your time and trouble and for responding so quickly.
@@OffGridGarageAustralia I will do my best to get four more batteries after this order is canceled.
Thanks.
Yea, Rick, you can only use 4 or 8 batteries for a 12V system. The video you linked above shows the setup as I described it in my first reply. parallel 2 batteries and do this 4 times. You will have 4 pairs with 2 batteries each. The put these pairs in series to achieve the 12V. Video will follow soon...
Very informative article keep it up sir I like it your presentation
Thank you!
Recently I did similar tests on my 150 Ah cells. On an individual basis the cells were fine, however, when connected two in parallel and then four of these parallel groups to make a 12 volt battery, I lost 25 - 30% of the capacity. I tried it several times moving batteries to various positions and got the same results. So I decided that the complex internal chemistry and internal resistance of the batteries caused some to drain more rapidly than others just as if you take different value resistors and put them in parallel the current through each will not be identical. Since it is the current that drains or charges a given cell it makes sense variations in internal resistance will cause variations in individual cell resistance and currents. Just as with parallel resistors, the voltage across resistors will be the same but the currents are different and I think the cell being taxed pulls down the voltage for the parallel set. Also, although my cells were fine as individuals and exhibited small cell differential voltages for most of the test of less than 10 mv (at the very end it got up to 30 mv) when connected in parallel I saw differential voltages of up to 300 millivolts. It would be very interesting to see if you could repeat my experience on your cells. For now I have concluded that if one wants a larger capacity battery than the value of the cells they own they should make single batteries of cells in series and then connect the batteries at the battery level in parallel with each battery getting its own BMS. Otherwise, based on my experience, you will lose a lot of capacity.
@@ursodermatt8809 That is kind of vague.
@@ursodermatt8809 This excellent research paper provides evidence for my conclusion and sheds a lot of light on the subject:
www.sciencedirect.com/science/article/pii/S0378775316309995
@@ursodermatt8809 Actually Tesla and everyone else does have this problem. A special BMS can be designed to deal with it or batteries can be carefully qualified to minimize the problem. Also, as you mention, Tesla parallels many, many cells. The loss of capacity from a bad cell is inversely proportional to the number in parallel. So a bad cell in Tesla's highly paralyzed case may be barely noticeable. I am sure Tesla handles it one way or another. However, in my case, I have just found found a bug in my Chargery BMS firmware that miscalculates the amp hours used by at elast 16%. Vendor told me to update to just released version of software that was supposed to fix the problem but just tested it today and it is not fixed. Still though, I don't think this explains everything I observed. I am guessing that I have a weak cell as well but it is hard to identify a bad cell in a parallel system because the good parallel cells makes the group voltage look okay. Or possibly the way I paralleled my batteries also may have contributed to the issue. But, in any case, turns out there are problems with paralleling batteries that in bad cases (mostly bad luck or ignorance) with some batteries can cause fire if not handled by a special BMS. I don't know if you read the research article I linked earlier but it also illuminates some aspects of the problem. In addition, Orion makes an expensive BMS and they have a lengthy discussion of the parallel configuration issues here:
www.orionbms.com/manuals/pdf/parallel_strings.pdf
This is right out of the Orion article:
"In the event that one of the cells develops a reduced capacity or high resistance (as is typical for aged or failed cells), the stronger cell will take more of the load and essentially prop up the weaker cell. In that event, the BMS is able to see a decrease in the overall capacity or an overall increase in resistance. With two cells paralleled together, a single weak cell can affect the resistance up to 50% and the capacity up to 50%. If three cells are paralleled, a single bad cell can affect the resistance and capacity of the total paralleled block up to 33% (with four cells paralleled, up to 25%, and so forth). As more cells are paralleled, a single failure becomes more difficult to detect, but redundancy is also increased since a single cell failure will have less of an impact on the overall performance of the battery. Cells directly paralleled with each other will
automatically balance each other since they are permanently connected."
As to your comments, the reason you lose a lot of capacity is not just because of current flow through internal resistance and eddy currents. The main problem is that the energy becomes unavailable because the parallel combination with an unhealthy or significantly different cell drops voltage quicker than it should and the BMS trips prematurely. Batteries are full of distributed resistance and energy such that you can actually have different voltages at different locations throughout the cell simultaneously. That is why when you stop charging or discharging the voltage you observe at the terminals will not be the same a few minutes or hours later. The charge in the depth of the battery actually needs time to migrate to the terminals. It all depends on a lot of variables. So a bad cell can pull down or up a good cell at the terminals and trip the BMS. Then, give it some time and the balance will work itself out again. A battery is not only modeled with a voltage source in series with a resistance, but also with another parallel string of a resistor and a capacitor. And, I suspect, it you really did it right, it would be modeled with a great many internal resistance and capacitance paths.
I am not sure what you are saying with your 500 ah battery and 10 ah battery example. If you put them in parallel at the same voltage they will probably sit fine but as soon as you charge or discharge them the 10ah battery is going to clobber your capacity and trip your BMS and/or melt. No way it can handle the current unless your load is trivial. You will have multiple problems such as mismatched capacity, mismatched internal resistance, etc.
Frankly, most people are just not aware of the issue because it is not widely discussed and most people don't really accurately and precisely test the capacity of large battery banks. Also, when they do test it is usually when the batteries are new and, thus, less likely to show a significant problem. It is also a hard problem to work around (as in expensive). Maybe they test one or two individual batteries or a few in series but often not much more. Folks settle for what they get and, given the complexity of the issue, that is not a bad choice. There are many versions of this problem depending on configuration. Let me give you one weird case example that can happen. Say you parallel at the battery level (not the cell level) and you, for instance, have two 4s batteries paralleled together. Let's say one of these batteries is in good shape with matched cells but the other has a bad cell. Further, assume each battery has its own BMS and that each BMS has a separate relay or Mosfet to control charging and discharging. So you would have a path for charging and a relay for it and a separate relay and path for discharging on each battery but the charging paths connect together at some point as do the discharging paths Okay, given the above, you go to charge your batteries and the good battery goes all the way to 14.6 volts while the bad battery has a bad cell that causes it to have lower capacity and it trips the charging relay when one of its cells reaches 3.65 volts and the other cells are at 3.3 volts. Okay, the charging relay for one battery trips early and the charging relay for the other trips at 14.6 volts. Seems good right? But it is not because the discharge relays also create a path to each battery and on creating a parallel path between the batteries the battery at 14.6 volts becomes a charger for the battery at a lessor charge. Since one of the cells in the bad battery is at 3.65 volts it is now going to overcharge as the higher voltage battery transfers charge into the bad battery. If the voltage mismatch is big enough you could even have a melt down. Play with the voltages and number of bad cells in this configuration and you can see that you could have a battery overcharging a cell to more than the 4.2 volt never never land. Even if you do not have the problem now, you might as batteries age.
I know that the example above is not the config used in the video but if you read the Orion article it discusses the issues with many different parallel configurations including some similar to that used in the video.
Point is, it is more complex and interesting than most folks are aware of but I don't know just how big of a problem it truly is. If one does not notice a dramatic event like a big loss in capacity of a meltdown the issue may never be found or accounted to battery aging. I'd sure like to see the capacity of the batteries used in the video actually tested both in series and in parallel. It may be that it will work out fine because the batteries are matched and/or my BMS problem over-exaggerated the issue and/or busbars between every terminal of the parallel groups cuts the issue. But I sure would like to see the tests by multiple people and various configurations so we could get a better feel for the situation. The issue does exist but I suspect it causes a capacity loss that few actually know about (or maybe care about).
By the way, you need to use multiple instruments to monitor amp hours, Watt hours, voltages and currents because I use 3 simultaneously and they all give different answers (which is how I found my BMS firmware problem - two were close, my manual calc. was close and the BMS was far off). In the end, I will probably build my own test instruments because I actually have a degree in Electrical Engineering (although that was a long, long time ago).
Thsnks for this video I'm about to do the same exact thing with a diy 18650 battery and this video just saved me from making an error. Just curious, while you're learning all of this stuff, who/what are your main sources?
This is a great series. I’ll be building a battery for my camper soon. I’ve never used Alibaba. These batteries seem to deliver as promised, why did you choose this battery and this vendor?
This was the only vendor which offered 5 years warranty on the cells and also was with Alibaba for over 8 years. I have found cheaper sellers but went with them and so far, so good!
Next time you order batteries, order 2~3 battery testers extra. They tend to die out after some use, better to have backups than to be left stranded in the middle of a test.
Hey Andy, looks like you're on a winner with these batteries, so with 16 that give you around 13kWh (probably 10kWh usable)
That's a "Normal" days driving in the Teslander ?? I'm still battling with my Outlander PHEV, but am looking at the MG PHEV when it arrives
in Australia, hopefully Q1 next year.
Merry Xmas mate, happy testing !!
Andy :)
Go full EV. I know two people with the MG ZS EV.
Battery pack will give me 14.5kWh of which I can utilise 100%.
I use only 4-6kWh for the Teslander per day for my commuting, so that's definitely a green light for this project.
Could you share how to choose a BMS unit to match the battery bank? I am not quite sure about what amp value would appropriate. Pls advise. 🙏
Please ask the supplier 16 with delivery to Macedonia what is the price.Dont have experience with Alibaba.Ty in advance and god bless you.You are great keep up the videos ☺️☺️😉😉😉
Great job that was awesome👍👍
Thank you! Cheers!
Thanks so much this was very educational and also very encouraging to see that these batteries which are probablly the best value you will find anywhere online (believe me, I've LOOKED). I have a question though, why can you not leave these batteries fully charged for too long, what would happen and how long would it take before there would be an issue? Is it safe to leave a battery at 90% capacity?
Thanks for your comment and feedback. Due to chemical reactions, the battery will lose capacity when charged to 100% and kept at this stage. This will shorten the life if you do this to often. You can charge to 100% of you are discharging it right away again. The chemicals inside are most stable at 50% state of charge (SoC). Everything below or above will shorten its life. 90% is far better than 100%, 80% is even better. If you want to store your battery for a long time charge it to 50-60%. For general use, you can use it from 10-90%, better from 20-80%. If you want the battery to last a really loooong time charge from 30-70% only.
@@OffGridGarageAustralia Thanks for the response! Ok wow that's really something I had no idea about. It makes me wonder what the manufacturer's mean when they say the battery is good for 3,500 cycles. Are the assuming when they give this number that the battery will be each day discharged and charged to 90% capacity or is the 3,500 cycles the really best case scenario of only using the battery in the 30 - 70% range? Sorry for the questions but your a wealth of information and i'd be kicking myself if I did not ask.
@@bethechangeme2233 so, the specs say if you do depth of discharge (DoD) between 10-90% you will get 3500 cycles. If you do 30-70% DoD is more like 10.000+ cycles.
Batteries in satellites do only 40-70% so they last 25 years reliably.
@@OffGridGarageAustralia it would seem that one would need to triple the required size of their battery bank to stay within the DOD of 30-70% in order to make them last the 25 years yet if the DOD is between 10 and 90% that same three battery banks would last 27 years! Would it be safe to say forget about compressing, forget about super tight DOD's just go for the 10% - 90% and in 9 - 10 years we will have better technology?
Those little energy meters NEED to be calibrated. Their tempco isn't very good so the only way to get reasonable results is calibrating beforehand. I think most of them want 20V 1A as the standard. Some do allow you to use a known voltage and match but I don't think that's one of them.
There is nothing in the manual. Where do you got the info from?
Too bad my Island is Long Island, We geek in very similar ways. We would have a rip.
I ordered batteries on your recommendation and they came in garbage.I thought I found a solid supplier but so far this is the worst quality I have bought:)
👍 Yes Test Akb. 🔋 LiFePo4
Interesting! You took a pretty rough procedure with 0,79C with high environmental temperatures. Data sheet says 0.5C and 25 celsius and I remember (didn't memorize the source) that after activaton you need a bunch of complete cycles to reach full capacity. Discharging with 1C will reduce the capacity at 3% and high temperatures (data sheet mentions 55 celsius) can reduce with another 5%. So I assume the capacity will exceed 280 under ideal conditions. Sounds good to me. Would be nice to reproduce the same test more times of the same cell for verification (etwas Deutsche Gründlichkeit kann nicht schaden ;-) ) Funfact for me was the changes between the different releases of the data sheet (mine: www.lithium-powerstore.de/media/products/akku/datenblaetter/eve/akku_eve_LF280.pdf - May 25th, 2018 )
Thanks, helped some. Why did not the official .2C test ?
Maximum discharge current is 1C not 2C
@@grahamjones6712 mind the . The accepted capacity test load is .2C
That tester can't handle .2C (56A).
@@grahamjones6712 He said "point 2C" (1/5C), not 2C.
In the old days THE REAL old days the Phone company A T and T had some kind of battery systems so the system always works in a outage huge capacity .
They still make those they're called tubular plate lead acid they have about a 20-year life expectancy pretty expensive and heavy
You can purchase them in a 3,000 amp hour 2 volt each cell
Great video Andy would love to build a system like that but it's to expensive in tax to buy chinase battery's in Denmark
Try those: www.aliexpress.com/item/1005001715950047.html
They have free shipping to Europe and seem to be tax free. They're way too cheap but hey - nothing ventured, nothing gained... 😉
Just made a test, it will cost 345$ each cell and I have to buy 20 cells before they ship to Denmark
Fantastic result on capacity Andy. Thanks for sharing that. Looking forward to the discussion on compressing batteries of this type. One commenter noted that the readout on the load was showing the internal resistance of the tester. I think that's right. 3.2V / 23A = 0.139 Ohms. The voltage drop from terminal to terminal of 0.14V (combined)
6:36 that's the external resistance, not the internal resistance of the cell. That other tester does show a measurement of the internal battery resistance, and it's done by using the difference between the battery voltage with no load and the voltage under load, and divides that delta by the load current. I did that separately and the meter readout for internal resistance seemed reasonably close. The no load voltage is based on your configuration setup of the meter for 100% SOC, so you have to do that right before that test.
The battery label showed 0.15 milliohms for internal resistance, which has nothing to do with the hundred plus milliohms of the 0.139Ω external resistance that the load meter measured.
Awesome nice work
ah das gute digital multimeter von conni! :)
25 Jahre alt und geht immer noch 😉
The resistance measure 0.14Ohms and the effective resistance the battery is discharging over. 3.24V/23.1A=0.14Ohms. its not the internal resistance of the battery..
Merci très intéressant
KEEP YOUR WORK GOING ON PLEASE I LOVE UUU
Pass! Excellent
Guys, is it just me or the video is flickering quite a lot around the 1:30 - 2:00 mark?
If the lights are not flickering, it is just a camera issue. Take your phone and look through the camera at a tv, computer screen. You will see weird flickering, because the cameras are slower at picking up the lights. Not a problem either ways. If the shed was running on solar and a cloud came on top, voltage dropped, would cause the bulb to flicker as well if connected directly.
So this battery as 12V 280ah with an inverter would run a window A/C unit drawing 5ah 500wh at least 7 hrs basically ?
More like 5 hours. Your inverter will only be 85-90% efficient. Plus losses in cables.
Plus 5ah at 110v is more like 550w.
Recon you only want to be using 80% of these lifepo4 batteries to maximise life cycles, so don't drop bottom 10% or charge over 90%. Will increase your life cycles from 800 to 1000's :)
@@w3bb0y luckily the devil is in details . the room to b cooled is 1/4 the cubic ft these window units are rated for . previous attempts with agm 500 ah have only used 40% d.o.d. on 8hr runs so I'll b giving the 280s i try in summer . should b interesting .
The cells are great for 20-30a applications. Could you share with us a picture of the QR code on the cells. Is it QR code 02YCB66710000J ?. I noted your Alibaba links does not state it is EVE cells. I think it is EVE copy cat cells, but thats fine. The sellers only state in the private comments that it is EVE cells. Real EVE cells can deliver 1C
Thanks for mentioning that...how can you decipher the characters resulted from qr code to tell the manufacturer is EVE or not?
Many thanks
Whhat company did you buy these cells from?
All info is in the description.
Since you're working with such low voltages and you have to be accurate down into the millivolt range do yourself a favor dump the cheap Chinese meters. Get yourself a fluke 87v or 289. You will never have to worry about whether what you're reading is correct. It will be. you can bet your life on it and many professional electricians and technicians do everyday. Also if you can find a good Weston cell you can check the calibration of the meters. These can be a bit fiddly as you have to keep them at a known temperature to ensure the calibration is correct. you also cannot move them or you must let them sit in place for a day or two for the chemicals to settle back out. If you must use the Chinese meters at least get a known voltage reference that is calibrated and is referenced back to a known accurate source. One item is known as a DMM check source. These are available at dmmcheckplus.com. They're not $20.00 but they're also not expensive and would be very helpful to verify your equipment accuracy. A basic unit is $123 and will give you a precision 5 volt AC and DC source plus a current source and a resistance standard. For an additional $20 you can get a capacitance reference source. And there is an optional case if you would like it. Also the manufacturer offers a low-cost recalibration for 20 bucks. This is one of the best deals in calibrators that are built and tested out there.
Acurate dummy load ....Aliexpres....13$
"9.99A 60W 30V Constant Current Electronic Load Discharge Battery Tester"
Is best there is ....SKY RC MC3000 calibrated.....Is as reference....also have 4 wire voltage measuring....
Keep supporting CHINA!!!
sub'd I love my 280's
Thank you.
cut short man take forever
Your lights are killing me