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My new 272 ah Lishen cells arrived

Dave (Boog)

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May 18, 2020
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My 272 ah Lishen cells arrived, thanks to Michael Caro. I haven't been able to test them yet but I am very excited. They only took 7 weeks from the time I ordered them with Michael to arrive. I had originally planned on a 24 volt system, but have decided to go with 48 volt, so I will be ordering another 8 of these cells. Now to get them top balanced and tested.

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Hello @Campin May I ask how you top balanced your batteries? In parallel, or in series with a BMS? Just got my 32 Basen 272 ah. Need to determine best way to charge; all 32 at one time or in sets of 8? I have a 20 amp PS. Thank you! Jerome
 
Unfortunately I haven’t had a chance to do anything at all with my cells. I’m new to this too, but do a search on top balancing. There are several great write ups on the subject on this forum. But for initial balancing, I don’t think I’d try to do all 32! Maybe groups of 8. And after you get all 3 groups topped off, put them all in parallel to balance them. But definitely use a BMS when you are trying to top them off. It’s too easy to destroy your cells by overcharging them if you don’t.
 
Hello @Campin May I ask how you top balanced your batteries? In parallel, or in series with a BMS? Just got my 32 Basen 272 ah. Need to determine best way to charge; all 32 at one time or in sets of 8? I have a 20 amp PS. Thank you! Jerome
Hi Jerome! I’m not the guy to ask in this case. 1) I’ll bottom balance and 2) no BMS. Cheers
 
@Javalord1 right wrong or indifferent i plan to top balance my 16 272ah cells by grouping them in 8s and charging with a bms to 3.45v, then connecting that 1st group in parallel to finish with a bench top charger to 3.6v.

While the 1st set is on the bench top I'll set up the other group 8s and charge to 3.45v and this time let the bms work on balancing thru its balance function. When the first set is done, I parallel the 2nd and finish up.

I'll probably fine tune the numbers, but something like that. Also plan to step balance unless I get impatient.
 
@Javalord1 right wrong or indifferent i plan to top balance my 16 272ah cells by grouping them in 8s and charging with a bms to 3.45v, then connecting that 1st group in parallel to finish with a bench top charger to 3.6v.

While the 1st set is on the bench top I'll set up the other group 8s and charge to 3.45v and this time let the bms work on balancing thru its balance function. When the first set is done, I parallel the 2nd and finish up.

I'll probably fine tune the numbers, but something like that. Also plan to step balance unless I get impatient.
Sounds like a good plan, but I wouldn't limit the initial charge to 3.45v per cell (I assume you mean 27.6v for the pack, the cell voltages will vary). Charge them up to normal (at least 28.2v, that will get you much closer to full). Your BMS might kill the charge early if your cells are not well balanced, but there is really no downside to maximizing your initial charge so you aren't charging forever with a low amp power supply. That's assuming you have a working BMS with high voltage cutoff.
 
@Javalord1 right wrong or indifferent i plan to top balance my 16 272ah cells by grouping them in 8s and charging with a bms to 3.45v, then connecting that 1st group in parallel to finish with a bench top charger to 3.6v.

While the 1st set is on the bench top I'll set up the other group 8s and charge to 3.45v and this time let the bms work on balancing thru its balance function. When the first set is done, I parallel the 2nd and finish up.

I'll probably fine tune the numbers, but something like that. Also plan to step balance unless I get impatient.
I would recommend charging the 8S packs to 3.5v or even 3.6v for yhe top off just to make sure all the cells are at or just past the flat part of the curve. I did the same thing and used 3.45 and still had to individually charge the cells with anywhere from 1.5 AH to 60 AH.
 
for my 16S battery - After some trial and error with top balancing, the procedure I found that worked and was very easy was as follows:

I used an 8S hobby charger with balance leads for the two 8S packs. Actually I had two hobby chargers, one on the 8S banks, and one I was using for individual cell charging.

I charged the entire 8S pack to 3.6v, and there was one cell that topped off first.
I recorded the numbers of the cells that were still low, as the hobby charger tells you what the voltages of each cell are.
I use alligator clips and using the second hobby charger charged each of the low cells individually to bring each one up to 3.6 volts. You can do this while the banks are all in the 8S, or 16S configuration, not a problem. I like the hobby charger as they shut down when the cell(s) are charged.
I then used the 8S charger and did another balance charge after waiting for the cells to settle.
There were still a couple of low cells, I just charged those again as singles and repeated the 8S balance charge. After two rounds of that they all topped off properly when 8S Balance charging and the charger went into balance mode to finish off the top off.

When I put the two 8S packs into the 16S battery they were all still well balanced and close in voltage at around the 3.54v mark even 6 weeks later while sitting.
 
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