A123 cells BMS off the shelf?

[semiroundel]

Hi all, I have access to A123 cells at a decent price, I have an Arduino-based welder for the tags so could easily make up the packs (I've used A123 cells for a while in RC flight and my charger (Revolectrix) actually charges through the balance leads instead of through power cables, thus charging individual cells rather than bal;ancing them after the fact).
This depends on me charging in 2x 5 cell packs at a time, but that's only 10 cells, so to do an Ebike I'd take a long time and have to couple up packs.
So I'm looking for an intelligent BMS dedicated to A123 or at least generic lifep04 chemistry, Any ideas?
I live in UK so European source only or China.
TIA

 

[owhite]

I know these links dont last very long but I'm considering using one of these:

https://www.aliexpress.com/item/4000822738214.html?spm=2114.12010612.8148356.1.395470ec6syKag

search on the terms: "bms 77.7V lithium polymer daly" on google.

bear in mind I'm on another thread where we are discussing the merits of this battery and BMS:

https://endless-sphere.com/forums/viewtopic.php?f=14&t=107913 and I should NOT be considered an expert.

 

[AHicks]

One of the reasons I have no interest in building my own pack was learned through the need for a pack to balance charge in radio control. To make that possible, the individual cells that make up that pack must match in voltage capacity very closely. Trust me, they can vary widely! To get 10 cells that match close enough on any order for 10 cells would be pretty lucky in my estimation. You would likely have much better luck buying 15 cells and not using the high and low cells - just using the 10 that were closest in voltage. At the very least, it's something you should know going into it. Make sure your supplier is shipping matched cells!

Best of luck!

 

[owhite]

Again, I am NOT an expert, I came here to learn.

For example one member pointed out the role of the BMS is NOT to help with balanced _charging_. Hey, I thought it was, but my mistake there.

However, on this thread:

https://endless-sphere.com/forums/viewtopic.php?f=14&t=107913

the point is being made that if you have reliable batteries - you can charge large strings (e.g., a bunch in series) and check the voltage levels manually (which I assume means put a voltmeter on them while they are charging) and look at their levels to make sure nothing is wildly off. Then, use a balanced charging approach on a periodic basis to make sure they're balanced.

I did some searching and have not found any balanced chargers that go beyond 10s, but this looks like it could work okay at a low amperage
https://www.amazon.com/EVPEAK-1350W...rds=10s+balance+charger&qid=1598395554&sr=8-7

It would be great if other people with knowledge of charging approaches for A123 packs would shout out their experience.

 

[999zip999]

Great A123 20ah cells maintain balance . How big a pack what for ? These are big heavy battery when in a pack. Mine 7yrs old 1.520 charge cycles no BMS just me @ 80 amps. I just bulk charge and monitor. I have two thru the sense wires balance charger but never need it. What cells ?