I have tried the bluetooth bms active balance, its very slow. It keeps new cells very balanced, but it’s too slow to balance a pack that’s so far out like this.
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I used the active blancer on two lipos charged differently to see if it works. It didn´t work at all in my case. just drained some cells and charged to one other cell, but the result was far from balanced, even after all leds switched off.
Idk if I can trust that pcb ever. I mean you never know if it really work or not till your pack get out of balance over 0.1V. So if you use it on a battery which is in an enclosure and you not open up that thing regularly you might find out it doesn´t work when it´s anyway already too late.
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Anyone tried this one? Much more expensive but maybe it works better. It looks big so it would be better to just leave a connector on the board.
or maybe this one?:
That expensive one seems to have reasonable reviews
That second one isn’t an active balancer - just a really big set of bleeder resistors like is in most other BMS boards. It just bleeds off the extra power as heat, rather than actually using it to charge the low cells.
Fiori that’s normal if lights not lit it’s mean balanced you wait until all lights are off done balancing. Sometimes, not all lights are lit just wait several hours you’ll notice all lights are lit and starting balancing all your batteries. The bigger the battery pack the longer to balance. Mine 13ah 12 hours to balanced everything.
One thing about active balancing is that it will take much longer as it is charging other cell not burning its power through resistor which is pretty fast compared to charging.
I know they turn off when it’s done balancing. But If you look at the progression of my photos you will see that it was not balancing correctly regardless of what the lights say.
The first 5 cells were drained to below 2.8 while the rest were at almost 4 volts.
If the active balancing is in fact charging at what it states(1.2Amps) then it should be able to balance out this 6AH pack overnight no problem. Or is it 1.2A total balancing power split over the 12 balancer switches?
The time progression in my photos is about 35 hours. I feel that would.be plenty of time for it to balance out at that rate.
I have that bottom type, I haven’t hooked it up yet. I’ve wired it up to an aviation type plug and plan on using it externally, far too big to mount internally. The big resisters are THM and look pretty delicate. I’ll post back when I’ve tested it.
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I think its 1.2A total no way those small inductors would be able to withstand 1.2A without super high switching frequency which I doubt it has 
Also it makes more sense 1.2A / 12 = 0.1A / cell
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did you say it’s also connected to the bms at the same time as the balancer?
Yea a Bluetooth bms. The balance on the Bluetooth bms is turned off
I’m going to manually charge the lower cells as close as I can get them and see if the balancing will improve.
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for shits and giggles try unplugging the balance lead harness to the smart bms.
i have no idea what that’ll do, but see if it makes a difference?
doing some awesome science for us here
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An active balancer really should use flyback transformers as this would overcome the limitations people have encountered with this BMS.
I designed one a while back, never brought it to fruition because I couldn’t figure out where to buy a bunch of small flyback transformers.
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