Top balancing my cells, but something happened!
ฝัง
- เผยแพร่เมื่อ 27 ธ.ค. 2024
- Guys, this happened to me last night when I worked on the battery. I changed the connection of 8 cells from series to parallel and forgot to turn around one cell! I was lucky I had only 2 cells connected when this happened...
Before building your own battery, you should always top balance your cells. Only this will ensure they have the same state of charge and are ready to be connected in series.
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So glad you share the “negative” with the “positive” because we all experience the “negative” sometimes and can learn so much also “NOT to do”. :)
Enjoy your videos!
I shorted 2 cells as well...ONCE!!! I learned very quickly. Thanks for your videos. I enjoy and look forward to them. We learn together, and I thank you for that as well!
Thanks for watching and you feedback!
I am building my first battery as I watch your videos. You are so right about putting tape across the terminals as you install or rearrange the bus bars. I didn’t, and yesterday one of the bus bars swung onto the opposite terminal. Major sparks, scary moment! And the bus bar got so hot in a fraction of a second that it totally discolored. You can bet I will always use gaffer’s tape from now on. Thanks for your inspirational videos.
Do both screws finger tight before using a wrench to tighten. Loosen both but do not fully remove a screw before loosening the other one. The second screw keeps the bus bar from pivoting.
Wow, thanks for sharing. Scary stuff...
@@Sylvan_dB That's a fail-safe 'best practice' for sure. Thank you!
Good job, most people would not admit their mistake on TH-cam. Hopefully your cells are OK. Keep up the good work!
Thanks, cells are fine, it was only for a second. But scary anyways...
You are only human Andy. But a bigger man than many as you admit your mistake. It helps keep all of us more aware of the inherent danger of playing with lots of lap.
Thanks Wayne :)
Almost happy to see we all make the same mistakes. Learning will always be a process. Very happy to see the new shelves. The timber between the bus bars had me worried. It could have shorted as a result of moisture, dust build up or even and ant line.
Keep up the great delivery, as I'm really enjoying it
Do not use the screws. Many cell terminals were destroyed by it.
Use studs with nuts. Also it is advised to put an isolating layer between the cells.
The most used practice in the industry for top balance is to charge them first to 3,5V ... and only after this is finished to full 3,65V.
Some suggest even to charge every cell separate.
I have been wondering studs vs bolts. my second set of 32 272Ah cells arrived with bolts. the 1st set of 32 272Ah cells arrived with studs and nuts with 3mm hex hey required to tighten in the studs.
I don't think it's necessary to charge them individually. What are you doing with them afterwards as voltage will drop a bit over time and they are not the same anymore. 3.5V is already 99.9$SOC, so not really a point charging them all the way up.
Studs... yeah thinking about it... I need them at least for the main pos and neg of the battery with the bigger cables attached.
@@OffGridGarageAustralia For a Tesla like (some 100 or 1000 cylindrical cells) battery this is the only real solution. After full the cells V drops into the cell relax V. That is not a problem. The cell is still on 100% and only this counts. V value can be deceiving: Voc =/= Vload.
I would advise to use the studs on every terminal. You do not have a tight fixture around the cells (they will move a little bit), and the screws are not all the way into a not very strong alu terminal .... so far from ideal.
your inverter will thank you if it does not get too hot; yes put it outside the cabinet for better cooling. definitely. keep up the good work. 😎😎
Thanks, will do!
anything you walk away from with fingers and toes intact is always a winner and a good reminder to respect the zappy bits!
Hahaha, yeah, right 😁
I shorted mine a couple of times. Dropped a ratchet extension on one, just rushing to undo the bolts by hand and it slipped. BANG! 😮
and another time my ratchet handle shorted between the two terminals. I’d insulated the handle with heat shrink, but the very end of the handle was still exposed and of course that was just the right length to reach the other terminal 🙃
Ouch, that sound terrible. You would think you are getting more careful over time, right?
@@OffGridGarageAustralia haha. I am getting more careful. Most of the time 🙃
Thanks Andy. You can’t be too careful.
I had my positives marked with red electrical tape, negatives with black tape, just to avoid any chance of stupid errors (which I’m very capable of doing.)
Also I like the idea of using thin insulated electric cable during balancing- would act like a fuse long before any significant harm could be done, and wrap ANY tools in electrical tape before using. I heard of a guy who dropped a shifting spanner across his battery, scary stuff.
I’ll say it again- you can’t be too careful. Cheers
Well done so far! You are absolutley right about short circuts by batteries: There is flowing a lot of Amps which can be very dangerous.
I'm a German and following some german solar channels as well. (off course!)
I don't know how good is the knowledge of german language who read this comment ...
But if you understand have a look to the channel Solaranlage
The guy (NOT ME!!!) who run this channel has installed the same batteries as here mentioned. He gave some safety tipps for protecting tools (Very simple, but useful) and advised to isolate each battery because the housing of this batteries are the PLUS pole. - As long the paint cover is intact all ok; but some deep scratches maight lead to a desaster.
However: May be it's interesting for the one or other ...Good luck with your project!
Yes, the in-rush amperage is so high that it will melt any metal instantly.
Dimitri ist geil. Bin schon aboniert und gucke fleisig.
Yes good work learning all of us. Keep it up. Best regard from norway
Thank you!
Ich hätte gerne Dein Gesicht gesehen, in dem Moment wo Du gesehen hast, das gibt ein Kurzschluss. 😄 Das zeigt nur, immer vorsichtig sein. Niemals sicher fühlen. Danke das Du so ehrlich warst, Fehler passieren. Gut das nicht mehr passiert ist. Danke.
English please
Yes, English ;)
I would have liked to see your face at that moment, there is a short circuit. 😄 That just shows, always be careful. Never feel safe. Thank you for being so honest, mistakes happen. Good thing nothing worse happened. thank you
Good video I have shorted a 200amp packet battery before made me move very quick you have to be very careful take care and ya no ring put one in your ear 👍😎
Hello Andy. Please, never ever wear a ring when you are working on batteries! If you make a mistake and a short circuit happens, you will have a very big problem! The very high short circuit current
will glow up the ring. You could suffer severe burns. In the worst case, you can lose your finger. Greetings from Germany.
Thanks Stefan. I consider the chance the ring will make the actual short as very small but yeah, you're absolutely right.
Not sure If I can take it off after 27 years 😁
Great job!! keep them coming!!!!
Thanks! Will do!
Safety First!! Newb here but from what I can tell the discharge rate of these batteries is crazy and probably the most dangerous part to them.. Something like 2C so you could discharge a fully charged bank in like a half hour.. That's a lot of juice you have there.. Be careful my friend.. I'd like to see more videos from you.. :o)
The short current is more like 5C and even higher. Internal resistant is super low with only 0.1mOhm.
Hi Andy, I have also lived through a heart stopping 'short' situation, not fun! To reduce the exposed terminal risk I got cut 90mm storm water pipe cut it in half length ways and lied it along the line of terminals. Cheap easy cover. My terminals where larger, 40 mm pipe might suit your better. Keep the videos coming 👍
Great tip! Thank you.
Another good reason to top balance, is the BMS is really good at protecting (disconnecting) the battery bank when the first cell drops to the low cut off voltage.
The BMS is not nearly as good trying to equalize cells at full charge.
I do recommend the tape, and keep both screws in the bus bar at least hand tight before using a wrench! The second screw should be in before tightening or loosening a screw in a bus bar. This second screw stops the bar from pivoting with the first screw.
Edit: You should also remove or tape over your ring while working on your battery. Very dangerous to wear a metal ring around that kind of current.
Great tip. Thank you. You mean the metal ring needs to come in contact with the positive side and also the negative terminal at the same time, right? I know what you mean but think this is very unlikely to happen unless you maybe work with un-isolated tools?
Thank's from Norway. God work
I prefer the bottom balancing method applied individually to each cell. All cells can reach a minimum of 2.5V but not all can reach a maximum of 3.6V. The parallel top balancing method causes stress in the cells that reach the maximum value first because they continue to have to receive a load until the others equalize and reach this maximum voltage. It's my idea. Congratulations on the excellent work and videos. I want to see more!! :)
Always good with safety goggles. I have also seen these Daly BMS es are pretty popular it seems. Anyhow looking forward for next video! Stay safe.
Thank you.
yes i put a piece of red tape on the positive end of every cell. I then used a Dymo label maker and typed out positive and put that on top of the red tape. I shorted 2 cells about 1.5 months ago. I had to step back and do more safety things. gloves, eye protection. I used the tip of a plastic caulk gun to flip the busbar off but it ruined 2 studs like an arc welder. teaches you respect for 544Ah shorted... safety 1st.
It may be safer when balancing in parallel to connect them with light wire that will act as a fuse should an accident occur. Great explanations Andy.
Thanks Ben, yeah like a balance cable or so which just goes off in smoke in case of a fault...
@@OffGridGarageAustralia I'm just going to use telephone wire -the thinnest single strand insulated wire I know of that is cheap.
@@MiniLuv-1984 and you use this instead of busbars?
@@OffGridGarageAustralia For the initial balancing when I connect all 16 cells in parallel - yes. 22 guage wire is ok for 2 o3 amps and I expect will act as a fuse at 10 or 20 amps.
@@MiniLuv-1984 that's not a bad idea.
Thank you very much!! I am just starting my first solar generator build and your calculations have helped me a lot.. What I'm building is much smaller but the math still works.. My project will be in storage a lot and I want to get the longest life I can from my batteries so I plan on keeping the charge between 20% to 90% and store it around 50%.. Your work on the solar charge control settings was great.. Just a quick thought from a newb.. When you install the batteries into your cabinet flip the positive leads around to the battery from the BMS so they match up with the app you are using.. Thanks again!! Keep up the great work!!
Thanks a lot for your comment and suggestions. The batteries will go in a box, not the cabinet.
what kind of fire prevention do you have Andy?
btw i am going backwards through your videos from time to time. lots of information and you are a joy to watch.
thank you a million amps at 48 volt!
Thanks Wiley. The battery is in a separate building away from the house and in an area with metal shielding. The battery storage is made of metal altogether. All safe.
Hi Andrew... This is why I am so interested about your videos (apart from you being funny), because you talk about stuff other channels just assume we know. I have seen people use retractable sleeve to cover 80% of the busbars, minimizing the possibility of positive and negative busbars getting in contact by accident while rotating during screwing and unscrewing, I think that is a good idea.
#buildthebattery
Another great tutorial. Looking forward the next video!!!
ahahahaha you silli billi - I did that with a balance wire - damn thing went up in smoke. IN MY HANDS. Luckily I was wearing heavy gloves (like you should do when working on batteries). Lots of smoke and melted cable. Doesn't take much ;) Stay safe mate. Enjoy your videos. Sydney Australia here! :)
Thanks for your feedback, yeah, it goes bad quickly once it comes to this point. I did many shorts with batteries before but these ones are just... HUGE!
I shorted out my eve 280ah cell the other day. Busbar slipped and there was a massive spark. There's now a black mark on the terminal and I've had to order another battery as the pack won't balance. The shorted cell shows normal voltage until I begin charging, at which point the voltage jumps up over 3.4v. When I stop charging the voltage falls rapidly to 2.5v I will always put tape over the cells from now on!
Oh, wow, thanks for sharing. I didn't expect the cell from being damaged though this.
Your busbars worry me. They are straight, without the little bump bend. The batteries swell as they are charged and i think the bump is there so the batteries can swell without putting tension on the busbar and battery connections. What do you think?
I've got my cells 2-3mm apart... It'll be in one of the next videos...
Just tuned in to see some magic smoke. But nothing happened! So sad. Compared to a welding machine, a short between those 280Ah cells is way stronger. But at some point pretty much self healing ;-)
I think I was lucky!
@@OffGridGarageAustralia I wittnessed somebody accidentially droping a wrench onto both poles of a car battery. Half of the wrench just bursts into pieces.
The frog is called Sheila, as the cells seller ;)
Sheila is very professionell, the frog is disturbing our hero while Video TH-camn. This is not fair for Sheila. The frog shall be called Donald and shut up
Hahaha, you guys! 😂🐸
Everyone accidently does that short at some point! Glad to hear it was quick and no issues in the Heat of the PANIC!💥😎👍
I think I was lucky the bars were not screwed down to the terminals yet and had proper connection.
A Big thumb up from France ! I'm following many if your videos and learn many things. Ans Il adore your accent ! (That is bettet than mine if course 😄). Go on giving us these splendid videos. Thanks
My smartphone trranslator changes words without my permission. 'If' instead if 'of', 'ans' instead of ''and'. Sorry, I should have read back before sending my message....
Thank you! 😃
What accent do you mean though?
@@OffGridGarageAustralia Hi ! Everyone's got an accent. It's a little bit of ground of our origin as said a french writer. I wish you all the best 👍
@@sylvainpelletier9667 thank you. Stay safe over there!
How you doin. Your videos are really good and interesting ive learnt a fair bit from you thankyou. I have one question about top and bottom balance. I have a set of lithium prismatic battery which is 5s 2p but the bus bars are spot welded so I cannot unbolt them to balance. I only have a 5s bms atm will that still be fine.
G'day Craig. The cells in 2p config are already in balance, so your 5s bms may or may not top balance or bottom balance. What I mean is has the bms got a balancing function.
@@aussiescotty2950 thanks for the reply but being new to all of this I couldn't tell you . I really would like to no much more about it.
Yes that's cool I'll try and send a picture of my modules. I do have the set of three. They are max 21v each it maybe easier in Gmail. Mine is craigivas@gmail.com.
A BMS should balance these cells?
@@OffGridGarageAustralia Hi Andy, I think I have seen some BMS's that don't balance but just protect from hi/lo voltage, hi discharge etc. So checking the specs is essential.
Do I need to compress new cells before top balancing?
Is it possible to make bus bars out of regular 12 stranded wire? I dont have enough bus bars and figured since it was low volts and amps 12 awg should work?
Keep up the good work I really enjoy your videos. One thing that might be worth considering is removing any metal rings or watch straps or at least wearing insulating gloves them as these can get very hot very quick if you short them.
I haven't found the right gloves yet. Looked in the hardware store and they have rubber gloves but the feeling is not the same as without.
Hi, thanks so much for your videos, im buying 8 Eve 280 ah cells and dont intend using them for up to 2 months so can I just connect them all in parallel and let time do its balancing for a month or two?
Freddy frog might be an idea keep well from South Africa
WOW, you were lucky.
GREAT Videos.
I have one (1) favor to ask.
Could you show this old guy how to properly connect (8) for a 2P 4S for a 12 volt system.
I don't really want to bother you and I know you're busy.
Thank You for all you do for us all.
I really like your box setup.
I'm thinking of super gluing two 24F battery boxes together for my batteries or building one out of an old wine bottle case I have.
Hy Rickey
up.picr.de/40353042ao.jpg
This is the topview of a 2P 4S battery with 14 busbars.(without BMS or cell-balancers)
hand walter
! weight of 8 cells 5,5Kg each = 44Kg !
2p means make one logical New Batterie by connecting plus - plus and minus - minus. 4s means to connect minus plus Alternating. This will life the voltage from 3.3 of one cell to 13.2 volt of 4 cells. If you combine both techniques you connect four (2p cells) to a nominal 12v System. No warranty!
@@BischesseHunting I don't see how to connect them. That is what I need, to actually see how to connect 8 batteries into one 12 volt battery.
@@guohuaye12 2 steps to understand:
A.) Build a 12v Batterie out of 4 cells with 3,3 Volt. You know how this works?
B,) take 2 cells with 3,3 volts and 280Ah and Build one logical cell with 3,3 volts and 560Ah. You know how this works?
C.) Is the next step AFTER A and B
@@BischesseHunting Exactly, I don't know how to do A or B. I just can not see step A. in my minds eye. I have 4 cells of 280 Ah.
I can not see step B. I'll have 4 cells of 280 Ah batteries.
I was hoping for a picture or video.
I was told by someone else this is called a 2P4S or something.
I have a 100 amp BMS I bought for a 12 volt system.
You can reduce chances of shorts by using heat shrink on your bus bars, just leave the ends clear.
I see you have some already insulated, just heat shrink the rest similarly. A cheap and simple solution to a potential disaster.
Also either heat shrink or buy insulated shaft screwdrivers, insulated wrenches and ratchet just to reduce risk.
Some bus bars have already heat shrink. In this case it would not have helped though.
Understood, but I'm hoping to prevent a further incident.
One of my roles in the oilfield companies I worked for was the Lithium battery safety officer, the last thing you want to see Andy is a lithium fire if at all avoidable 🙃
You said after top balancing it’s normal for them to drop in volts.
After mine top balanced to 3.65 I eat sit for a couple hours then put into series and let sit over night. The next night after work they have already dropped to 3.367. Is it normal to drop that much?
Also I have read articles that say when they are done being top balanced they need to be discharged as soon as possible to get them down from full charge so it doesn’t hurt the cell. Unless I missed it I don’t see where you do that? Do you need to that?
Hello been watching your videos I was wondering whether you could tell me on BMS 100 do you need 100 and battery
How can we help?
@@OffGridGarageAustralia hello sir I was wondering whether you could tell me with a 100 and power battery that the BMS should be rated at 100 amps
What voltage is your charger set at when you have those cells in parallel and top balancing? What brand/model charger are you using. Evidently a variable voltage charger of some sort.
3.65v is the safer top voltage and any Lithium charger like Turnigy or icharger is fine. If you have an active smart balancer then top balancing isn't required.
@@neliosamch3195 Top balance is always the wise choice. Even with a 2A active balancer because you charge it with >20A.
Also top balance is mandatory if you have cells in parallel. Like with a 2p16s (2 parallel and 16 series of this pair). Even more with a lot of small cells parallel.
@@mrzed6597 I have 11A balancer to keep 16S in balance. Batteries may not be new. Lifepo4 batteries voltage get very unstable after 3.4 v so is better to charge them to 3.4 top voltage.
@@neliosamch3195 For top balance 3,65V (even with a 11A balancer) if you charge the pack with more than 10A can happen that one cell is long full and you still charge it (overcharge). After if you charge only with 3,4V then charging is slower, you do not use the full capacity of the pack ... but it is safer.
There is very few (almost none) scenario where not making top or bottom balance is safe.
Many user made Tesla like (18/26 cylindrical cell) packs burn out because top balance was not implemented.
@@mrzed6597 NMC (nickel-manganese-cobalt) can cash fire even if properly balanced. th-cam.com/video/4ED_FRcfG2Y/w-d-xo.html On the lifepo4 battery the capacity is between 3.4 or above 3.1 @ 1-10A cafe.foundation/blog/wp-content/uploads/2010/10/typical-lifepo4-discharge-curve.jpg
Hey Andy if you don’t get to respond to this I understand as I know you’re quite busy. I ordered 8 EVE cells from a place in Texas. Got them yesterday, inspected and found scratch/pock marks on the terminals. They are supposed to be new but the marks make me wonder. They all tested 3.28/9 volts.
They all seem to be sucked in a tiny bit at on the longer sides at the top only. They are not swollen at all.
Does it sound as if they are used or class b?
Hello to sunny Australia. Andy, I am building my first PV system (600W, 12V) and batteries are on the way. I do not own a charger which could be set to 3,5-3,6V. So I consider to, firstly, connect batteries in parallel and wait untill they are more or less self balanced. Then, I would connect them in series with bms (Daly - I should have watched your videos sooner) and charge them using solar panels until bms stops charging. Thanks to you, I would know that at least one battery is at, lets say, 3,5V. Than, I would reconnect the batteries in parallel and let them self balance. Than, I would reconnect them back in series with bms and charge again. I would repeat this proces until all cells are top ballanced. Would this method even work and is it suitable for the first top balance?
Btw, thank you for sharing your knowledge with us.
You need some shrink tube on that screwdriver or there will be more sparks...
I use insulation tape on all exposed metal parts of tools I'm using
I thought it's more fun to use this one?
But yeah, you're right, if I drop it, the fun will be over.
I did the exact same thing. Forgot to turn battery 😡 I was very tired when working on it
Hello
I am doing top balancing setting the voltage to 3,65V, when cells are in parallel, but i cannot reach more than 3,30V on the cells intensity still 2A.
Normally the tension drop in the cable should be 0,01 V 1,5mm2 0,5m 3,65V and 2A.
Do you have any idea ?
Thanks
What about a device that works as a bms but has an extra feature that shuts down the batery when it goes below 20% soc and also disconects when going Over 80 ou 90% soc? Without rellying on the voltage .. just using the couloumb counter and going from that... Is there such a thing?
Quite sure the sbms0 of electrodacus can do this. But it is only working with 24v not 48v. I am in the process of building 24v 1120Ah 8s4p with These eve 280ah cells. Works with wifi and can be integrated in iobroker, knx and Telegramm. Lots of stuff to learn...
But how accurate is the coulomb count over time. I know the one in the vehicle I had before the Tesla was not very accurate and needed re-calibration from time to time.
@@OffGridGarageAustralia i have a small running sbms0 with 8s 150Ah and the SOC is very exact, +/- 1% and it is reset to 100% as sonst as the end of charge is reached, in case of any deviation , these will not sum up oder time
The quickest way to learn not to make a mistake is by no making a short!
That sound so easy when you say it 😂
Hi Andy
‘‘Tis is
Jan Knabe ein verpflanzter Germane in Texas.
Great video. I am exactly in the same process buying batteries from alibaba. Any additional advise. I have a 8 kw solar installation and want to buy 32. 3.2 v 280 Ah That would be 28 kw. This is now so cheap. I am waiting for ur next entertaining video.
Thank you! Wow, that's a big system! I thought mine is already relatively large but people are going nuts with these batteries. So great to see.
Was machst du in Texas?
My 32 cells are at dpd from Sheila to me, going for 5KW pv with 24v 1120Ah and sbms0 from electrodacus. Which bms do you use in texes
@@OffGridGarageAustralia what BMS are u using!! I will have a 48V system can u make any recommendation? Thanks
Ich bin passioniert kunstschmied und arbeite mit glass in the kiln den ich habe. Wenn du lust hast kannst du mir dein email schicken dann sende ich dir einige bilder von meiner anlage. Gruß. Jan
to help with expanding batteries put a bump in your busbars
I guess that was your "demon core" moment... luckily it's just batteries and not plutonium you're working with there, but scary enough! ;)
It was unexpected for me that it happened at all. What a major fail of all I'm saying all the time...🤦♂️
Hi Andy.
For the sake of your viewers, please take a look at the charging chart Thad you display in the video, and compare it to the one in your data sheet.
I know it says lifepo4, but it is not correct.
Thx.
I know, it was just for explaining the curve so viewers know what I mean with 'steep curve'.
Great video, again! What do you expect to run (and amp hours) with that battery bank, and how long will it last? I need more bus bars too! Where can you find them for these batteries without going to China?
Peter Rock, There are many DIY copper busbar tutorials, common to take copper pipe and smash it flat and drill holes in it to make your own bar.
@@jamesbsa6450 Copper busbar and aluminium terminals not the best idea. For a short time fine, but for long time not. Galvanic corrosion. Needs a special washer that one side is alu other is copper (melted together)
@@jamesbsa6450 That is what I was going to do if I couldn't find a vendor. Thanks!
@@mrzed6597 good to know. Do you have a source for the bimetal washers?
@@jamesbsa6450 The magic word you have to search for is CUPAL :) You will find.
Great tips and info, love your open mind and exploration. Would you ever consider making a revisit on your videos with your favorite comments and valuable feedback? E.g. By providing an update a person new to the channel or video can see you dig under the hood further with things you may not have considered prior to the comments? Anyway keep up the great videos!
That's a great idea!
Na sowas, ich habe genau den gleichen Kurzschluss fabriziert und auch die Schraubendrehermethode angewandt..... ...
Was man so macht im Eifer des Gefechts 😂 Hat man noch Glueck, das die Kontakte nicht schon zusammengeklebt waren.
@@OffGridGarageAustralia Der Zelle hat es offenbar nicht geschadet. Die 24V- Bank läuft problemlos .
"I hop into the pool" I don't "like" you anymore - my pool is no covered with snow - so unfair 🤣
About tools (skrewdriver, keys and so on) - isolate their bare metal shaft with some tape or some shrink tubing
Yep, I've got another full isolated set but like this one more. It's my preferred screw driver...
@@OffGridGarageAustralia Just put some tape over it or some other kind of "Verhüterli" and you are on the safe side - better save then sorry!
stop with the in and out of the bolts in to the batteries. Buy studs with an allin head tighting
All good.
There is never a reason to do bottom balancing. The people that came up with the idea did not wanted to use a BMS and had no idea what they where doing (DIY EV's a few years ago).
Top balancing is what is needed and if you have new cells and did not played with them (Like you did) the BMS will take care of the balancing. The BMS will protect all cells from over charge and over discharge so in that example with eBikes the BMS will just warn user to stop the eBike not to damage the battery and eventually start reducing power available to motor then disconnect before any cell gets below the minimum set limit (depending on type of cells).
At 3.55V the LiFePO4 cells will be at 100% SOC (maybe 99.9 still basically fully charged).
Thanks for the inside and explanation. That is indeed very interesting. Some people still don't use a BMS for they setup. Do you think there are cases where this is still appropriate?
@@OffGridGarageAustralia Batteries are expensive so it seems as a bad idea not to use a BMS as it is almost impossible not to damage them without BMS.
Because I designed and sell a BMS I may be considered biased but a BMS costs a fraction of the cost of the battery so not sure why anyone today will just want to use the battery without a BMS.
There is just no application I can think off where a bottom balancing will be useful and all available BMS IC's are designed for top balancing.
Thanks for your quick reply. I've seen a few videos about your BMS. It seems to be one of the best on the market. I'm considering upgrading mine in the future as I only bought a basic one to get started.
I agree with your argument of comparing battery and BMS costs. It makes no sense not having one.
@@OffGridGarageAustralia If I remember from other videos you want to build a 48V system and SBMS0 is only for 3s up to max 8s so 12V and 24V systems. You can contact me by email and I can provide you a free SBMS0 to play with (no stings attached) but you can not use it for your main 48V system.
I only design products that are compliant with the ultra low voltage standard and that is 60V to 75V depending on the country so with 24V a 60 cell panel is ideally matched and that is already over 40V open circuit voltage and the 72 cell panels are around 50V open circuit thus with 48V battery you need two of this panels in series and that means 80 to 100Vdc open circuit voltage and well above the safe ultra low voltage standards.
Great. Thank you for this offer and I will definitely get back to you on this for a future system then. I've seen on your website that you support only 8s/24V systems max. Makes sense from a safety perspective. Any plans to go bigger and support larger systems in the future? You probably cover most setups with 3s-8s for DIY usage, and not too many people build 48V systems or higher.
Put labels on everything...make it idiot-proof. It's no shame when you consider safety. Research reveals people can handle 7 items in short term memory.
From driving commercially I have observed that I have variable attention. For this reason, some employers do not even allow coffee cups in the cab, because reaching for the cup detours the thought processes required for assessing risk.
In a day, we only have so many brain chemicals to process efficiently. i.e.: Being tired, hungry, thirsty, distracted, long day on your feet, an emotional phone call challenges our ability to maintain the 5 axes of safety requred to maintain our stance on the road.
If you think you are not affected by variable attention, or are are content to think you are somehow a good driver because you have quick reflexes, then you are fooling yourself. In commerical driving, merely having quick reflexes is not an indicator of good driver. There is no such thing as SAFE driver, only a SAFER driver, as driving, and electricity, is implicitly dangerous.
SAFER driving means establishing a certain stance through continually evaluating potential threats and making strategic micro-adjustments. The brain doesn't work as well when our awareness is saturated with stimulation, it works best when at ease. Your labels are like road signs.
Sure always tighten or loosen battery screws with both screws in after the initial torque loosen the second one before removing the first.
Of course everyone knows that, right?!