current to outdrives...

[lynnboy021]

my bro in law has a 36 italian boat he bought from someone in the satates well long story short the boat was converted from 220v to 110v and a new battery chager also... so he leaves his boat in the water all summer long and his outdrives are getting really bad by the saltwater eating them away so this year he cleaned them up and repainted them but while working on them he was always getting a shock when he touched them but not a big shock just a small one.... so i helped him test his 12v and 110v system to make sure that his 110v was not grounded when his 12v system.... well when i hook up my meter from his 110v black wire to his motor ground i get a reading and if i unplug his 110v i get no reading.... so i thought he had a broken wire and his 110v was touching his 12v system but it was not, so now he forgot to plug in his battery charger back and now i get no readings at all but when he plugs in his battery charger back in then thats when i get a reading from 110v black wire to his 12v ground (white wire and ground does not give me a reading just the black wire)..... my ? is should a boats battery charger send a current from the 110v to 12v ground??/ also his charger has 3 banks one bank for his starting battery 2 bank to his house battery and 3rd to someother panel box that has gauges and switches maybe like a transfer box i don now..... any idias/ thanks

 

[alldodge]

You need a galvanic isolator. In the pic below note the isolators on the grounds from each feed. There should be a main ground buss which all grounds are connected. The wiring below also has an inverter and generator so they may not apply to your setup.

Notes, you should also have a Mercathode or similar with outdrives to stop the corrosion. Also make sure all of the grounding leads from the drives, thru the transom and to the engine block are in good order