dnmun
1 PW
i made a hybrid pack of Ping pouches, 36V10A, and my ghetto headway pack, 36V10Ah by putting a second sense wire plug piggy backed onto the bottom one on a v1 signalab.
also this is the first one i used the DIP switch to turn off the circuit current. it works neat. just totally disconnects the battery. at the mosfets.
when i was balancing the pack, i had one cell that always pushed up to 3.90V and just hang up the charging forever, so to diagnose, i split the packs apart and put them on separate BMSs.
i left the cell from the headway pack on my v1 signalab and used another v2.5 signalab on the other sense wires from the ping pack. that side would drain the 3.88V off the sense wire from the ping cell, but the v1 did not drain the voltage down through the shunt resistor from the cell under the v1. this was #6.
so i measured the voltage at the reference leg of the 431 and it measured 2.70V when the cells was 3.88, and for the other cells under 3.65V the reference was all lower than the 2.495V used for the 431 voltage reference. this is the same voltage reference used in the chargers. except the chinese 431 parts seem to swap the position of the cathode from the fairchild part and instead the cathode is where the emitter would be in a SOT-23 pnp transistor. which makes sense.
i measured the voltage drop across the shunt resistor and there was no voltage drop across the shunt resistor so no current is flowing through the 431 and draining the charge through that shunt resistor. it is dead. the 431 is dead.
unsoldered it and replaced it with another 431 i had taken off a parts pcb. now it is balancing, i measured 1.7V across the shunt resistor as it drained down. fixed.
ps: i calculated the voltage at which the shunt in the voltage reference would turn on to be 3.54V from the resistor divider bridge across the cell and the 2.495V spec for the 431. so that is when the v1 starts diverting current around the cell.
also this is the first one i used the DIP switch to turn off the circuit current. it works neat. just totally disconnects the battery. at the mosfets.
when i was balancing the pack, i had one cell that always pushed up to 3.90V and just hang up the charging forever, so to diagnose, i split the packs apart and put them on separate BMSs.
i left the cell from the headway pack on my v1 signalab and used another v2.5 signalab on the other sense wires from the ping pack. that side would drain the 3.88V off the sense wire from the ping cell, but the v1 did not drain the voltage down through the shunt resistor from the cell under the v1. this was #6.
so i measured the voltage at the reference leg of the 431 and it measured 2.70V when the cells was 3.88, and for the other cells under 3.65V the reference was all lower than the 2.495V used for the 431 voltage reference. this is the same voltage reference used in the chargers. except the chinese 431 parts seem to swap the position of the cathode from the fairchild part and instead the cathode is where the emitter would be in a SOT-23 pnp transistor. which makes sense.
i measured the voltage drop across the shunt resistor and there was no voltage drop across the shunt resistor so no current is flowing through the 431 and draining the charge through that shunt resistor. it is dead. the 431 is dead.
unsoldered it and replaced it with another 431 i had taken off a parts pcb. now it is balancing, i measured 1.7V across the shunt resistor as it drained down. fixed.
ps: i calculated the voltage at which the shunt in the voltage reference would turn on to be 3.54V from the resistor divider bridge across the cell and the 2.495V spec for the 431. so that is when the v1 starts diverting current around the cell.
