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MB31 balancing, which power supply/battery tester

rgroothuis

New Member
Joined
Dec 23, 2024
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The Netherlands
I've ordered MB31 cells (16x) they still have to arrive, no details on voltage yet. Assuming I need to balance them, which power supply or battery testing do you recommend? I've seen the blue device: EBC-A40L but this is another 200+ euro's. Any good alternatives?
 
I use the BMS active balancer which in my case is a JK PB.
Ok, thanks for your feedback. The battery box I've purchase also has the JK BMS with a 2A active balancer. So you installed all the batteries into the box and switched it on and leave it like that for a couple of day? What was your process?

And was the charger/inverted already connected? And charging the batteries?

Can you provide a bit more details? Thanks.
 
Ok, thanks for your feedback. The battery box I've purchase also has the JK BMS with a 2A active balancer. So you installed all the batteries into the box and switched it on and leave it like that for a couple of day? What was your process?

And was the charger/inverted already connected? And charging the batteries?

Can you provide a bit more details? Thanks.
Yup my SCC charging settings are very conservative, 3.45-3.5v per cell.

As long as you are able to maintain system voltage so that cells are above 3.4v for few hours a day your cells will be under 0.010v delta way quicker than doing top balance.

Set it and forget it.
 
Ok, thanks for your feedback. The battery box I've purchase also has the JK BMS with a 2A active balancer. So you installed all the batteries into the box and switched it on and leave it like that for a couple of day? What was your process?
Assembled the cells in case and allowed PV to do the charging, if you have no sun then you wait. If they are badly out of balance when you first get to 3.45V cell V or you are impatient then use a simple lab power supply to charge the low cell while the rest and the low cell are being charged by the PV. Any too high runners can be taken down by connecting a car bulb across the 2 terminals. Once they are in balance at delta 0.010V then take the delta down to 0.008V.
 
Assembled the cells in case and allowed PV to do the charging, if you have no sun then you wait. If they are badly out of balance when you first get to 3.45V cell V or you are impatient then use a simple lab power supply to charge the low cell while the rest and the low cell are being charged by the PV. Any too high runners can be taken down by connecting a car bulb across the 2 terminals. Once they are in balance at delta 0.010V then take the delta down to 0.008V.
The other option is picking up an AC charger, you don’t need much current.

For the first charge slow and low does no harm. 5-10 amp and let it bake.
 
The other option is picking up an AC charger, you don’t need much current.

For the first charge slow and low does no harm. 5-10 amp and let it bake.
Cutoff current for those cells is 0.019 times its capacity at 3.45v and 0.05 at 3.65v so it will be 5.32A and 14 respectively. otherwise you are risking overcharging the cells.
 
Cutoff current for those cells is 0.019 times its capacity at 3.45v and 0.05 at 3.65v so it will be 5.32A and 14 respectively. otherwise you are risking overcharging the cells.
Can you explain this in a bit more detail? Is this about the charging profile of the batteries? And when you need to stop charging?
 
Cutoff current for those cells is 0.019 times its capacity at 3.45v and 0.05 at 3.65v so it will be 5.32A and 14 respectively. otherwise you are risking overcharging the cells.
And any quality charger will flop from CC mode
to CV mode as they get up to the charging voltage and current will fall off.

I use a very conservative charging voltage 3.45-3.5v per cell.
 

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