Quote:
Originally Posted by Volt_Ampere
He says that each pack has separate BMS so they are not really in parallel. Only the total packs are in parallel not each individual cell.
|
Hi Volt_Ampare,
I understood but re-reading my post, I realise I could written it a little clearer.
What I meant to say is that the individual PACK voltages should be identical as that are in parallel, that is providing both BMS’s are enabled of course.
@Lou,
As to only charging to 70%, you may have a bad cell that is tripping one of the BMS’s. How is your SOC meter connected? Is it a voltage type, coulomb counting type or is it integrated with the pack? If it’s the latter, how does it handle the fact that there are 2 packs? It could be that it’s summing the capacity of both packs, and you have one pack charging fully and contributing 50% to the SOC but the other pack trips off early, only charging to 40% and thus only contributing 20% to the SOC. If that makes sense.
A similar thing could be happening during discharge, reducing the overall capacity.
Although not as bad as series connected packs, parallel connected packs can also be troublesome. This is why I always recommend a single pack with a single BMS. Parallel connecting at a cell level with a single BMS is the correct way to increase capacity.
Cheers
Pat.