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Hi All -
I was wondering if anyone has figured out a way to use a battery protect or another device to disconnect at an over voltage situation, i.e. battery goes over 25.2V ( Tesla Module ), like the battery protect will do when I hit 19V on the low side.
If the BMS has an output contact why not use a DC contactor. if the BMS has no contact then maybe BMV plus a DC Contactor or Build your own BMS
https://hackaday.io/project/10098-model-s-bms-hacking
https://www.diyelectriccar.com/forums/showthread.php/tesla-bms-190266.html
There are even Latched (don't consume any energy while closed or open ) Bistable ( no energy consumption in both states) contactors
https://www.ev-power.eu/DC-Contactors/
https://www.ispacetek.com/DC-Contactors.html
Please note:
-BP is not to be used between inverter and battery (inrush current too high)
-BP only works one way
For protection of a lithium battery, a good way is to use a 'trip unit' to disconnect, I use a standard breaker with trip unit connected to it, the bms triggers the trip-unit if values go above / below the maximum settings (cell voltage, temperature). In normal circumstances this should never happen (inverters / chargers should listen to the BMS) so this is a good last resort. needs manual intervention to re-connect the battery.
If you are connecting them to a Multiplus then you could use the VE BMS to turn the charge or the load on and off, but you still need to sent the signal to the VE BMS unit this is easy to do as the connection sensing wire is a loop and there is a HV and a LV loop wire so its just a matter of open circuiting them when you want.
this way you don't need a solenoid or a BP if its ONLY the inverter charger and its controlled by the VE BMS unit connected that is and no other small loads,
