Third Battery

S

Salty Dog

New member
OK, I'm thinking of adding a third battery to the boat. I currently have the two mounted in the starboard lazarette with a Perko Off/1/All/2 switch. Question is, can I add a third battery and have it charged off the Honda alternator? Would this work if I put it in parallel with the existing house battery, or would I need a battery isolator (have found 1 alternator 3 battery isolators)? If I used the battery isolator, would I still be able to use the Perko switch to keep the starting battery fresh? I don't have shorepower, so the only way to recharge the third battery without the alternator would be to use a battery charger once I get home. Would really prefer to be able to charge it under way if possible. Any insights?

Thanks,
Jack
 
Hi FreighterGazer,
can I add a third battery and have it charged off the Honda alternator? Would this work if I put it in parallel with the existing house battery,
Click to expand...
Yes, I believe you can. If you now have (#1) starting battery>Perko (1) and (#2) house battery>Perko (2), a new (#3) house battery could be connected in paralell to (#2) house battery. This will add extra capacity @ Perko(2). You don't want to mix different types of batteries(starting-deep cycle) within one bank though. On Adeline, I have my house battery mounted in the port lazarette because there is no room next to my starting battery in the starboard side. I have my oil-tank there. And no isolator, just a 4 position swich, like you. My house battery is a gigantic group 31(66#) and fits nicely. You could do the same. Remember, the farther your run, the larger the cables need to be. Finally, shorepower and a built-in charger is a great set-up. Add a generator and your energy independent. Pete
 
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