Battery Sizes

[bthessel]

So the boat I bought has a group 24 AGM battery (Deka). If I want to add a second battery with a Add-A-Battery kit does it need to stay the same size? Group 24? Or can I do a group 27? It seems to be a lot harder to find group 24 AGM's.

 

[txav8r]

There are plenty of group 24 AGM's made out there, but AGM's are not as run of the mill as standard lead acid batteries. They are expensive and more stable, and they don't vent like a lead acid or spill. But you don't want to run two batteries in parallel that are dissimilar. So either keep them separated, or...use two batteries of the same age, type, size.

 

[PEARCE]

Both of my batteries are of different types and size. I've never had the need to run them in parallel so it's never been an issue. If I happen to drain my house battery by sitting and listening to the stereo to the point that the amps cutout I can still start both motors on the same battery. It doesn't take much to start our little motors. However, when the stereo quits on the house battery is when I just turn it off and leave it off.