adding a battery to a 2 battery system

[crazy charlie]

I have a 2 battery system for my cruiser.1 battery is for the port engine and all accessories including the fridge.The other is for the starboard engine only.I also have a switch on my dash to parralel them.Can I add another battery to the port side by running pos to pos and neg to neg??? I dont need to add it but would like to if it were not a project. Charlie

 

[Rhadley]

Re: adding a battery to a 2 battery system

Electrically speaking, you can parallel the 2 batteries (pos to pos, neg to neg) and stay at 12V with more current capability. I can't speak to the possible practical drawbacks; if 1 starts to go bad, will it harm the other one?

 

[Ralph 123]

Re: adding a battery to a 2 battery system

CC,<br /><br />I run a 3 battery system for my twins. 2 dedicated starting batteries for each engine and one house battery for all the accessories. They are all connected through West Marine Battery combiners. This configuration insures you never have to futz with switches and you'll never be get stuck no being able to start your engines. The all get electrically isolated during dischare and equally share the charge during normal opeartion.<br /><br />If you want more details just post and I'll see if I can post a schematic.<br /><br />The problem with just parralleing is if one of the batteries goes bad, the good battery will just discharge right into the bad battery leaving you with two dead batteries. At least connect them through a 1-2-all switch so you can isolate them.