# of batteries and what type?

[Tomm]

I only ever remember two batteries in my boat but the guy at my marina told me that he thought my boat needed three batteries. I have a 1985 Hunter 40. I want to put fresh batteries in so what do I need?Tomm

 

[Trevor - SailboatOwners.c]

Depends on loads

Hi Tomm -In planning a DC battery system, the most important initial consideration is what your loads are. Make a list of every electrical component on your boat (lights, nav equipment, stereo, refer, etc) and estimate the daily loads you need to power. Once you understand your needs you can size batteries (rated in amp hours) accordingly. I recommend grouping batteries of same type and size for a house bank and using a single separate battery for starting. Recommended reading: Nigel Calder's BoatOwner's Mechanical and Electrical Handbook (See related link).Best,Trevor

 

[Anchor Down]

The Guy at the Marina?

Just who is this "guy at the marina"?I imagine a H40 would have two deep-cycle batteries comprising the house bank, plus a separate starting battery for the engine.Pull up the boards, disconnect the house bank, and hit the starter with the battery switch set to "1" and then set to "2". If the engine cranks at either setting, you have a starting battery lurking in your boat somewhere. If you can find the starter motor, you can trace the line back to it.