I just picked up an 03 Ford E350 with the 7.3L turbo diesel and ambulance package.
As part of the ambulance prep package there is second (possibly aux) battery mounted on mid-right frame rail, as well as two alternators.
Question: is this secondary battery required for engine startup of the diesel or am I able to isolate it and utilize it for "house" power such as small DC fan and lights while not running. I would have a shop isolate and install a meter to monitor charge left but don't want to compromise the functionality of the vehicle.
Any advise is welcome and appreciated.