13s bms on 12s battery..... is this possible?
- Thread starter nanni
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eee291
100 kW
No one can tell you how to it. It depends on the BMS and some can't be rewired for less cells.
You will have to try and see what works.
You will have to try and see what works.
eee291
100 kW
At first I would leave the 13th wire unconnected. If there is no power at P- try charging it, some BMS need that to activate.
If it still doesn't activate the output, try shorting the 13th wire to the 12th cell.
If it still doesn't activate the output, try shorting the 13th wire to the 12th cell.
To know for certain without experimentation (which may damage the BMS input / sense lines in ways you won't know about until you test them for HVC and LVC response, and balancing function), you would have to check with the BMS manufacturer to get their instructions for this specific model BMS. Sometimes sellers of BMSs have this information and publish it on the page they are selling it on, so you could check with the place you bought them from, too.
Otherwise, experimentation per eee291's advice can be done.
JackFlorey
100 kW
It will absolutely work if you add a "fake" battery to the top (i.e. a boost converter that always looks like it's at 3.6 volts or something.)
You can also hack the board to remove that comparator, and wire it to always indicate "OK."
Seems like a lot of work to avoid another $50 BMS though.
I have used similar bms units with fewer cells. Connect the cell 12 and 13 wires together and put them on cell 12.
If you leave a wire disconnected it can pick up noise and false trigger a fault.
If you leave a wire disconnected it can pick up noise and false trigger a fault.
docw009
1 MW
If you find that BMS on amazon, there's a review where a guy explains how it works on 12S on what to do with the 13th wire.
I bought one off amazon, and it worked. I liked that it has an LED for each group that lights when the group is at max charge. Then it goes into balance, and eventually all 13 led's come on,
I found the quality mixed though. Some worked. Some never seemed to balance.
I bought one off amazon, and it worked. I liked that it has an LED for each group that lights when the group is at max charge. Then it goes into balance, and eventually all 13 led's come on,
I found the quality mixed though. Some worked. Some never seemed to balance.
batteryGOLD
100 W
test different combinations,
12S pin unconnected/floating, 12S pin( last but one ) connected to pin 13S( main + )
if none case work.. use just one cell connected at pin sampling 13S--12S to simulate a 13S battery from 12S (any cell possible charged at 50% SOC..) and add it on top of battery.. this is a very dirty solution..
test battery doin full charge until cut, and full discharge until cut. to make sure bms "S emulation method" is workin..
only possible to monitor low cut voltage(remember to monitor battery volts during full charge and discharge process)
top voltage cut not possible to know, unless battery debalanced and some element exceds 4,23V or 4,25V(where all bms should cut..)
anyway, do you trust at dirty electronic tricks or you prefer to go on a new 12S bms?
test to trust!
Last edited:
docw009
1 MW
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