Odd battery, auto size
 

One of my clients has a large rental that had the beginnings of an emergency, earthquake type lighting system installed. It was to have a 12 volt back up that would be kept routinely charged. This was installed (partially) by her previous maintenance man who expired from cancer several years back.

It was never finished, she has no interest in finishing it, not sure she really understood it from the git-go. Among the uninstalled parts was a battery labeled 12v, 65 AmpHour. It looks like a typical auto battery but has unusual posts, about a quarter inch looking thread rod sticking up an inch or so for each terminal.

It says, "factory sealed, do not open vent caps or it will void the warranty." I'm thinking any warranty is history at this point (4 years later, no receipt) so I opened them and only one has any visible water in it, and that one is low. My voltmeter shows a charge of 12.01 volts (?!).

Beats the hell out of me. I have a step van with a chev 6.2 diesel - two batteries - both of which need replacing, amazing they lasted about 10 years. It's largely on mothballs, but still valuable, I start it once every few weeks, it has a 2' x 3' solar cell on top, I installed it, that keeps the batteries topped off. I'm hoping to use this for one of them.

I can't find any info on the web. My guess is I should top them off with distilled water or highly filtered anyway, charge it up and see what happens. I'm hoping the fact that it's never been used will mitigate any damage from being low on water. What I don't understand is why it would be dry at that age, no use, if the vent caps are never supposed to be removed.

Often they use gel batteries in these applications. if it is liquid like water, then distilled water will be best. For these systems they use deep cycle batteries, not regular auto ones. They dont have as high amp capacity but hang on much longer.

I found some info online, didn't find it at first, they said that water does not need to be added. More I think about it, probably wouldn't be good for auto use. I might just try to sell it for the use it was meant for. They retail for around $200.

Does it look like this? It sounds like the standard backup sump pump battery to me...

http://www.homedepot.com/h_d1/N-5yc1v/R-100054931/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

Sounds like a standard deep cycle like for an RV or trolling motor.