Dual Battery Installation

Urband · #1 (**permalink**) 03-25-2002

I currently own a 7.3 S2 sloop with a Johnson 9.9 Outboard. There are times I go on an overnite and the single house battery I have will not last two full days. Is there any way that I can use my outboard to charge my single battery? If there isn''t, I would like to hook up a second battery. I have another main switch I can install that has the option for using the #1 battery, the #2 battery or both. My current GUEST battery charger is only a single bank charger. I assume I will need to get a charger that can charge two banks at one time.

1.) Are there any suggestions on how I should wire in the second battery?
2.) How about feedback on the type of charger I should get?
3.) Is there some special hints in hooking up some type of diode to prevent the inadvertant discharge of one of the baterries?
4.) Are there any references I can use to evaluate wiring/hook-up options?

regards,
Bruce

Peter_pan · #2 (**permalink**) 03-25-2002

Bruce
I''ll try to keep it clear. I don''t think a 9.9 O/B has an alternator unless it has a battery starter. If it does then it can be used to charge both batteries. Wal-Mart and most auto parts stores have battery isolaters. They''re the same as tho one''s at marine suppliers but are usually a little less money. They''re pretty simple to hook in. If you have no alternator. Install the switch. You can set the switch to all and your charger will charge both batteries simultaniously. I suggest at least a 30 amp automatic charger as a smaller one will take all day and all night to top off most deep cycle batteries. I use a D8 for the house. It lasts more than a night or two for sure. I seperate my house from the Nav lighting and Nav equipment too. Perko has an over-kill sized switch for a system your size that most boats use with multiple batteries. They too come with simple instructions for installation. I''ve never seen a failsafe system for the inadvertant. If all your using your batt''s for is lighting and Nav equipment you don''t need any wire larger than 10 gauge to hook it all in with.
Hope I helped.
Ole Pete