I just published this video, talking about balance and trying to demonstrate its effects (and lack of effects). This may be specific to DIY OW, where it’s often misunderstood. But, it may be worth sharing here.
20 Likes
Thanks for making this video. It all makes sense, but does it hurt to start passive balancing at 3.8v or even lower? I use llt bms not ennoid if that matters.
I’m not sure that would help much. Most BMS units with passive balancing, the LLT included, have bleed off current of something like 30-50mA.
At 3.8v per cell, the charge rate is still full speed. It doesn’t seem like a useful place in the charge cycle to make small bleed off operations. Might just end up making more heat, and not really show much improvement.
Also, if a pack needs so much realignment that the bleed off has to happen so early and for so long, it should probably be manually realigned, or the condition of the battery reassessed.
At least, those are my thoughts.
I have been able to shrink the delta by reducing the value down to 3.8. It wasn’t bad to begin with really, just my ocd over the delta widening kicked in, but I wondered if it stressed the cells leaving it at 3.8… However, I wasn’t thinking about the stress that I’m instead probably causing to the BMS.
Great video! This really helped me grasp top balancing vs. bottom balancing and the voltages involved.
You learned me something today 
, thx for the video