What to do with an old battery?

We have a 2004 Moomba Mobius LSV we bought four years ago. It has a single battery, standard stereo. The boat sits in storage, sometimes for several months. My son recently wanted to take the boat out and the battery was dead. Given the age of the battery and since we couldn't find anyone who would quick charge it, we bought a new battery from the dealer for $89. The dealer checked the old battery out and said it was still good so we took it home and put it on the trickle charger. It is now fully charged. The question is, what should we do with it now? Should we keep it as a manual spare or should we think about putting it on the boat and hooking it in with an isolator or perko? The batteries are identical marine starter batteries from Interstate (I think). Eventually (year or so) we would look to upgrading and adding some tower speakers and amps. What would you do now with the extra battery? It might be nice to have it hooked in as a more or less automatic spare.

(Message edited by wakeshoe on August 02, 2008)

If you do put it in the boat you should isolate it from the other battery via perko or something else. The difference in batteries could be bad for each other possibly killing your new battery if you ran them straight together. It would be of great benefit to have a backup battery.

but if they are the same type of battery which it looks like they are you can just parallel them together. I would do that it will give you better stereo life. This is the quickest and easiest way to go but won't save your butt if they drain where as a Perko would allow you to chose between the 2 batteries. I use an iso/combiner but I run my stereo equipment off of one bank and my cranking off another.