battery charger wiring


Member III
HI there, Does anybody know if I can hard wire a ProMariner ProSport 20 battery charger directly to the AC side of my panel? I can't get through to ProMariner. It looks like the PO did that with the ProSport 12 now on board.
Thanks so much!!

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
My 1988 panel has a dedicated circuit breaker on the AC side for the battery charger, and that's what we've always used. Does your have this one? Since the boat was built it has had three different chargers wired to this breaker.


Member III
Yes Loren I do believe it has one also, but was not sure if the new unit I bought could be wired to it. I can't seem to find anything out at the ProMariner website, and can't get thru to their "help" line. They advertise a direct wire unit they say that will handle heavier 4D and 8D batteries, but there is no need for me to spend that kind of money.
Thanks for your response

Frank Langer

1984 Ericson 30+, Nanaimo, BC
We have a 40 amp smart charger, Powermania brand, that can charge 3 separate batteries. It came with a plug, to plug into a normal 120 volt AC outlet. But the installation instructions also state that one can cut off the plug, and wire it directly to the AC panel.
Although I'm not an electrician, I can't see how it would matter if it's plugged into an AC outlet or wired directly to the AC panel, as the amount of voltage should be about the same.


Sustaining Member
My '85 also has a dedicated charger circuit breaker on the AC panel. I am presently replacing an old defective 20amp charger with a new ProMariner 40amp. The old is under the starboard lazerete in the cockpit which is a good 15+ feet from the AC panel and the port house batteries the cabin. The old charger is hard wired to the AC panel charger circuit breaker switch. The new charger will be mounted under the chart table next to the hull (where my knees won't hit it), only 3 feet from the house batteries and AC panel.

I am using a volt meter on the OLM side to track the wires from the old charger to the panel battery charger breaker, so that the new will be hard wired exactly duplicating the negative bus points for the black ground wire and the white (case bonding stud ground wire) and the positive connection at the charger switch (which will be changed from the black wire seen below to a red 8 ga to the new charger).

The relocation will eliminate a lot of wire under the sole and the new AC wire from the panel to the charger and DC wire from the charger to the house batteries, will be per spec in the ProMariner instruction manual, including all fuses. The old charger location was in the way and being hit every time we climbed into lazerete to do work under the deck.

Here is the back side of the AC panel. The AC master switch is extreme right (3 o'clock) and the battery charger switch is just behind and it. Negative buss bar is at 9 o'clock and positive buss at 6 o'clock:


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