There's a break in the connection somewhere the rear battery is simply not connected OR your grounding point does not work, move it.When playing music in the front it reads 13.8 drops to 12.6 or soBack battery reads 12.5 and drops to bout 12.0 its weird
Clearly the rear battery is connected if it's dropping.There's a break in the connection somewhere the rear battery is simply not connected OR your grounding point does not work, move it.
rear battery should charge very close to the same voltage as front battery there's a lot of resistance going on somewhere.Clearly the rear battery is connected if it's dropping.