but you still do not know if it is the BMS or the cells that are bad. i don't think you have posted anywhere here that the shunt transistor tested ok. just that you wanna take the battery apart. you do not need 7 more since you can use the battery as 15S instead.
but you still do not know if it is the BMS or the cells that are bad. i don't think you have posted anywhere here that the shunt transistor tested ok. just that you wanna take the battery apart. you do not need 7 more since you can use the battery as 15S instead.
and he never identified if it was the cell that died for no reason, which they do not. or if it was because the shunt transistor for that channel is shorted which is common on BMSs that people accidentally short out to the battery by accident. i think that is what the guy wanted to know and never will have the answer to. one of the shortcomings of this place. one.
and he never identified if it was the cell that died for no reason, which they do not. or if it was because the shunt transistor for that channel is shorted which is common on BMSs that people accidentally short out to the battery by accident. i think that is what the guy wanted to know and never will have the answer to. one of the shortcomings of this place. one.
I do not know how to test the shunt transitor,but i was just thinking,the motor still runs on 15s,should it not shut down the bms because 1s is dead.I have pulled the pack apart and tried to charge the dead cell,it only goes up to 0.8v then with the charger still on drops back to 0.4v.
i explained a few pages ago. if there is a voltage across the shunt resistors then there is current flowing through them according to ohm's law. if there is not a current flowing then there is no voltage. if your shunt transistor is shorted current flows out of the cell through the sense wire and then through the transistor and then the shunt resistors back to the negative of that cell. when that happens the voltage on that cell falls to zero.
i explained a few pages ago. if there is a voltage across the shunt resistors then there is current flowing through them according to ohm's law. if there is not a current flowing then there is no voltage. if your shunt transistor is shorted current flows out of the cell through the sense wire and then through the transistor and then the shunt resistors back to the negative of that cell. when that happens the voltage on that cell falls to zero.
Ok, still maybe the cell(s) is bad, or maybe the bms killed the cell, we still don't know........ You need to check out your bms to see if it is charging that cell(s).
pauldo said:
Ok,i do not have the battery connected at the moment to the bms,the one cell does not charge.
e-beach,i charged the cell individually like your earlier post.
I thought the bms lvc would cut out when any cell dropped below 2.0v or what ever it is.
Ok, then it is back to checking the bms to see if it is working properly. Sounds like you need to review dnmun's posts and do your best to learn what you need to learn to test your bms for functionality. Or you can replace the cell(s) and see if they charge properly. The least expensive way is to discern if your bms is fully functional first...testing the bms will ensure you don't ruin the new cell(s) you might install.
You need to check out your bms to see if it is charging that cell(s).
