Just keep in mind a 36v battery sitting at 37.2v is roughly only 70% charged. A fully charged 36v battery will be at 38.16v (ish). And basically dead would be around 35v.

Most BDI indicators need to see a certain voltage per cell before they reset to 100%. Typically over 2.1v per cell. Its possible that after charge, voltage is dropping below this reset point before plugging into the machine.

When you check charging it should be rougly 2.4v to 2.45v per cell or 43v to 44v for a 36v battery.

When checking battery underload you shld see a max of a 6v drop. (Sitting at 38v max drop would be 32v underload.

Its possible a module has a bad connection, not getting proper voltage supply or wiring or what not but Id have to say 9 times out of ten when I have an issue with an electric truck it turns out to be a battery problem.

And if the truck detects battery capacity is below 20% it will put itself into lift lock out to try and force you to charge (which is around 2 bars)