solar charger for multi-bank for my boat

[islandskip]

Greetings all,
I'm looking for a solution to my problem. I'm looking for a solar charge controller that can charge three 12v batteries. One AGM battery for each engine and one 12v deep cycle battery used for house circuits. I currently use a Morningstar dual battery solar charger which is working just fine. My main issue is when my boat is on its mooring to keep the batteries hot for the bilge pumps. Any suggestions?

[ChrisOlson]

I think I would get two different controllers or chargers because AGM's have different charge settings than flooded deep cycles. I know of no controllers that can charge two different batteries at the same time with different settings for each battery.

Actually, starting batteries should not be connected to any parasitic loads like bilge pumps anyway when you're on the hook. That's what house batteries are for. You should only be able to connect the starting batteries to the house batteries in an emergency with the battery selector to start an engine with the house battery in the event you have a starting battery go south.

[islandskip]

Multi bank solar charger

I think I would get two different controllers or chargers because AGM's have different charge settings than flooded deep cycles. I know of no controllers that can charge two different batteries at the same time with different settings for each battery.

Actually, starting batteries should not be connected to any parasitic loads like bilge pumps anyway when you're on the hook. That's what house batteries are for. You should only be able to connect the starting batteries to the house batteries in an emergency with the battery selector to start an engine with the house battery in the event you have a starting battery go south.

Good points and thanks for the information. I need to check to see how it is wired. A friend of mine has the same question about a multi bank solar charger and he is using all deep cycle 12v batteries. He is looking to keep it simple with one solar panel and one charge controller for when he is on his mooring.

[ChrisOlson]

Well, really you SHOULDN'T need to charge the starting batteries on the hook. We got a sailing yacht now and used to have an old Chris Craft motor yacht with twin Cat 3406's in it. But our starting batteries were in one bank and the house batteries in another. We had a big knife switch in the engine room that had to be thrown to connect the starting bank to either the port or starboard engine. The only way we could connect the starting bank to the house bank was with the battery selector for emergency starting of one engine in the event something happened to kill the starting bank.

Different boats from different manufacturers have been wired differently over the years. But I think if you consider that starting batteries SHOULD be isolated from the boat's electrical system at all times, except for starting and when the engines are running so they can be charged from the alternators, your problem with the controller is greatly simplified because you only need to charge house batteries with it from the solar panels. I would be my feeling that if you need more battery capacity for your bilge pumps on the hook or mooring ball than what your single house battery can provide now, add an additional house battery.