I am plugged into 50 amp. house lights dim refrigerator shows error code battery condition panel had batteries down to 10v now back up to 11v after turning off all lights thinking converter going bad...
Or Batteries may have boiled out their fluids and now one has a shorted cell putting a big load on the converter...
While you are checking your battery cables look around for signs of boiled out fluids and also check inside the battery caps to make sure the fluids are OK. All cells must be covered by fluids or they will short out on you...