So much for my earlier BMS theory. Here's an example that seems to lack dissipative balance.
Not that its a bad 48V BMS. I might even buy it. But never going to balance anything by itself.
https://www.aliexpress.com/store/produc ... 69649.html
It just cuts off when any cell is deemed unsafe. I suppose that makes sense, since dissipative
balance can get hotter than you want next to a battery, and not keep pace with fast charge.
But this also puts all responsibility for charge balance on the external charger. And that will
require reliable connections to every individual cell, big enough to handle the shunt current.
The balancer I've built for my own 36V is made to fully shunt away 2A of overcharge, and
at 4.15V per cell, thats 83W! That much heat I want nowhere near a battery, and heatsink
is hefty enough I may leave off the bike. Not like I need full balance every time. Portable
dumb charger may target an average 4V per cell, or some reasonably safe lower number.
Was also working up an active balancer to efficiently and fully wring the full use every cell.
Check schematics in the technical section. I had this sim running on 4 cells, and looks very
plausible from a sim standpoint. But then I get real about it. Do I have the time to layout
such a monstrosity and build the custom 11 wind transformer? Will it squeeze more out of
low end imbalance than the extra weight I'd have to cart around? Might as well balance the
top at the charger, and trust in weight savings and keeping it simple....
I'll attach picture of the BMS in question, assuming the seller's link will eventually expire.
Buyer beware: Not all BMS feature balancing. Maybe for good reason, it depends...