Battery Switch questions

JimRP31

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I finally finished the major part of my refit. (see the SISI Refit Thread) When I went to start the engine before launching I had one dead battery. No big deal, I figured I can use the good battery to start the engine. The problem I had was with the switch set to both or 2, the there were not enough amps to crank her over. I think the dead battery was draining the good one but I am not sure. Does anyone have a good diagram I can look to confirm the batteries and switch are wired correctly. It is a Perko Switch. I want to have one primary engine battery, the second for GPS, Radio etc, but I want to be able to start the engine if necessary with either or both.
 

traditions

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38 Holland
Most battery switches have a post for each battery and a feed that goes to the starter.If you wanted to run your electronics from 1 battery you would have to run the wire to the post on the switch to that battery.It would not shut off when you turned the switch off.I have a wire to my breaker panel from the feed on the switch,which powers the panel with either or both and is off when turned offWhen turned to battery 1,battery should be isolated and off.When on both a bad battery could drain te good one..I never run on both,because they will not get a good charge together and if you have problems you run both down before you realize a problem and have no backup.Run on battery 1 one day and #2 the next or switch during the day.I only use both for starting.I wouldnt worry about having a seperate for electronics.Hope this helps.
 

jerseysportfisher

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dualBatterySglEngine441x370.gif
 

JimRP31

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Oct 21, 2011
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tiverton RI
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Willis Beal/RP 31
Thanks. Found a diagram on the Perko website. I need to compare that to how I have it wired today. The one item I would like to have power all the time is my am/fm radio to preserve the presets. Would the radio need to be wire separate from the switch?
 
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