Adding 2nd Battery...help

[redbeard58]

I have a Hunter 260 and would like to add a house battery. I have a Mercury 15 hp outboard connected to the battery that came with the boat. There is a has a solar panel connected to this battery also. I assume that this battery connects to my 12 volt panel for the lights too. da! I would like to move this battery to the port side and to just work the engine. Add a large house battery to starboard side to run lights and stereo. I know I need a battery switch and have found one with off/1/both/2 positions. Is there a way to do this and still get the engines altenator to charge both batteries when needed? Like putting battery switch on both when running engine? I would like to leave the solar panel connected to the house battery. Any and all help would be greatly appreciated...BLUESKIES AND HIGHTIDES...RB

[kmeeks]

Where are you located? I''m looking for small projects to help out on...I''m in the L.A. area.

[BeneteauMark]

One thing to keep in mind when adding a battery switch is whether your outboard''s alternator works like a car alternator or works on a magneto. If it works like a car alternator, you''ll need a battery switch with a field disconnect. This keeps you from blowing the alternator diodes when switching between batteries, or if you accidentally turn off the batteries with the engine running. If your alternator is of the magneto type, I don''t think this is a factor.

In any case, common procedure is to start the engine with the battery switch in the "both" position, then switch to the "house" battery after shutting the engine down. This lets the alternator charge both batteries while the engine is running.

One concern I have is whether the alternator on your 15 hp outboard puts out enough juice to charge two batteries. I had an alternator added to my 5 hp outboard, and it proved to be a complete waste of money.

Hope this helps.

Mark
"One Step Closer"
Lake St. Clair, MI