Lithiums in a motorhome?

[folivier]

Just ordered a Junsi cell logger and will plan to use that alarm port for the alarm buzzer. That way I'll have control over the voltage set point. When the BMS alarms at 14.2 vdc the L2000 is still charging at 35-40 amps so I'm not getting the cells fully charged. But if this doesn't work out like I want then I'll continue searching for a separate charger. I found a few options that will work from the Sterling at 60 amps, a few at 100 amps, even one at 200 amps. The 200 amp charger would be nice and twice as fast. The Volteq (Mastech) charger looks nice but I'm a bit concerned that the settings might need to be adjusted each time due to the vibrations from driving.

[T1 Terry]

Just a note to make sure you understand the alarm logger wiring. The black wire is connected to the internal logger frame and the battery neg cable, the red wire is connected to the black wire when an alarm occurs if the N/O option is selected pulling the red wire to battery negative potential. The red does not indicate it's a positive wire, a mistake that instantly destroys the little transistor in the logger.
Another point, the logger alarm transistor has a peak capacity of 0.5 amps, even a spike above that will kill the transistor.
Not that the alarm is only active while the fault is present, if it's cell over voltage, as soon as the charging stops the cell voltag will drop and the alarm will stop. Some form of hysterisis will be rwquired to stop a relay chattering between the on and off state if driven directly from the alarm port wiring

T1 Terry

[folivier]

Thanks T1 Terry! You probably saved me from destroying the cell logger. So if I'm understanding you correctly the cell logger does not power the buzzer, it only completes the circuit? If so then I'll have to use a relay to power the buzzer and trip the relay with the cell logger alarm output?

[T1 Terry]

A buzzer will probably be fine, just battery positive one side and the red logger alarm wire the other side. We have used smoke alarms with a great deal of sucess, just solder the wires each side of test button, you will need to extend the cables a bit. Because the smoke alarm is sef powered by it's 9v battery, it only requires the circuit between the black and red wire to close and the alarm will sound, after a few seconds delay. Some smoke alarms are easier to get along with than others, the fancier the smoke alarm, the more tricky the wiring is, the basic models are easiest to get along with.

T1 Terry