j bjork
1 MW
When I built the battery the cells were perfectly balanced at a little over 3,6V
It is a 13s5p with genuine, new sanyo cells and a cheap chinese bms.
I did not charge the batterys afterwards, I just connected the carger to see that everything works. I thoght it would be perfect voltage to store the battery until the bike was finished.
I think it could have been 2 mounth or so, before I was ready to use the battery. I noticed it had lost some voltage, I think it had went from about 46V to about 42V..
I thought it was a bit odd, but did not think to much about it at the time, but I charged the battery and started testing the bike.
Anyway, I started to get power cuts from the bms and took apart the battery. Every cellgroup was in perfect balance and about 3,9V I think. Exept the first group on the negative side, that had about 3,1V as I remember it.
I tried to charge, and it overcharged the other groups to 4,25 or 4,26V, and the negative group to 3,7V I think.
I then charged that group with another charger to 4,2V, it charged it with a little over 10Ah. It has been about a week since i charged, and the other groups have went from 4,26V to 4,20V and this group have went from 4,2V to 4,17V
I dont think there is something wrong with the battery, so I suspect the bms.
It seems to me that the easiest way to power the electronics in the bms would be to take the power from the first negative cell group. That could be the same on every cell count, the first negative is always precent. And probably a more suitable voltage for the electronics than the full 48 ish volt.
Is it possible that it is built this way?
It is a 13s5p with genuine, new sanyo cells and a cheap chinese bms.
I did not charge the batterys afterwards, I just connected the carger to see that everything works. I thoght it would be perfect voltage to store the battery until the bike was finished.
I think it could have been 2 mounth or so, before I was ready to use the battery. I noticed it had lost some voltage, I think it had went from about 46V to about 42V..
I thought it was a bit odd, but did not think to much about it at the time, but I charged the battery and started testing the bike.
Anyway, I started to get power cuts from the bms and took apart the battery. Every cellgroup was in perfect balance and about 3,9V I think. Exept the first group on the negative side, that had about 3,1V as I remember it.
I tried to charge, and it overcharged the other groups to 4,25 or 4,26V, and the negative group to 3,7V I think.
I then charged that group with another charger to 4,2V, it charged it with a little over 10Ah. It has been about a week since i charged, and the other groups have went from 4,26V to 4,20V and this group have went from 4,2V to 4,17V
I dont think there is something wrong with the battery, so I suspect the bms.
It seems to me that the easiest way to power the electronics in the bms would be to take the power from the first negative cell group. That could be the same on every cell count, the first negative is always precent. And probably a more suitable voltage for the electronics than the full 48 ish volt.
Is it possible that it is built this way?