Hi all,
Been following along for a while now slowly testing cells in the hope of building my own pack one day. Wanted to share an interesting failure of my LiitoKala Engineer Lii-500. Couldn't fine any refrence to this fualt before.
Been test cells fine then one got hot on me about 40degrees from feel of it. Tried anouther and that goes hot and the charger smells burning. That fun electronics are going wrong burning. Opened it up and found what I guess is the current sence resistor burnt and the mosfet shorted resaulting in 12V on the cell terminal.
It does suprise me that nothing worse happened to the cells (bined just in case), first one was in there a while not sure when the mosfet failed. There is a mosfet of the negative terminal but looks like a low voltage cut off (batt+ -> resistive devider -> gate) and a 300mOhm resistor as the only thing current limititing.
Makes for an interesting failure, as I hear moafets tend to fail short. What you could you add to protect to the cell? Do other chargers have similar regulators circuits? I mean this was cheap so there is that.
Tom
Been following along for a while now slowly testing cells in the hope of building my own pack one day. Wanted to share an interesting failure of my LiitoKala Engineer Lii-500. Couldn't fine any refrence to this fualt before.
Been test cells fine then one got hot on me about 40degrees from feel of it. Tried anouther and that goes hot and the charger smells burning. That fun electronics are going wrong burning. Opened it up and found what I guess is the current sence resistor burnt and the mosfet shorted resaulting in 12V on the cell terminal.
It does suprise me that nothing worse happened to the cells (bined just in case), first one was in there a while not sure when the mosfet failed. There is a mosfet of the negative terminal but looks like a low voltage cut off (batt+ -> resistive devider -> gate) and a 300mOhm resistor as the only thing current limititing.
Makes for an interesting failure, as I hear moafets tend to fail short. What you could you add to protect to the cell? Do other chargers have similar regulators circuits? I mean this was cheap so there is that.
Tom