I’m working on an E-350 with an ambulance package at work. It needed a lot of work and im on the last problem with the charging system. Was driving it and the volt gauge was only at 11 volts. Had to go in a store and it didn’t restart after that. Jumped it and got back to the shop and it was only reading about 8.3 volts. Well ended up being a bad alternator. I replaced that but now im getting odd voltage readings.

Im the system there is one alternator and 3 batteries. Two batteries in the rear compartment are reading about 15 volts and the one batt in the engine is reading only 12 volts. All cables are tight and all terminals are clean. I cant think of what else to check on Monday. Anyone have any ideas or work on these systems? I load tested all the batteries and the one in the engine was low so I replaced it and I’m still getting the same voltage readings. Any help would be great.

 

could be the voltage regulator on the alternator. You shouldnt see higher then 14.7 in "12v" auto systems