I have setup 4 X 300AH LiFePo4 batteries with 4 X JK BMS connected and talking to Venus OS thanks to dbus-serialbattery on RPI. This battery bank is located on a boat, but the same potential issue exists on VAN installations. Here it is:
There is a major concern if at any point the battery BMSs disconnect due to high voltage or another reason while the alternator is running, there will over voltage of way over 100V that is going to spike through the system (aka load dump) and possibly fry other equipment on the boat. In this setup I'm using WS-500 smart alternator regulator that could stop the alternator charging when the BMS is about to disconnect due to hight voltage. Even if the WS-500 executes stops charging, the alternator require about 500mS to stop generating to prevent the load dump. Right now Venus OS alarm and relay triggers ant the exact time the BMS issues disconnect command to it's MOSFETs. Obviously there is not enough time for the alternator to shutdown.
The question is can I trick JK BMS or Venus OS to trigger an alarm before any FET disconnect command is issued and is it possible to delay the FET disconnect let's say by 2sec just to be on the safe side? I'm thinking of setting the alternator stop change if possible for 50mV lower setting then the BMS disconnect voltage is set for e.g.
BMS cell over voltage protection: 3.600V
Alarm to be triggered (to stop any charging): 3.550V
Not sure if that could be currently set on Venus OS. Any thoughts?