GM-GMC: Batteries, deep cycle batteries, interstate batteries

Question
Harry - Thanks for being available.  I recently purchased a motorhome.  It had two Marine/Deep Cycle batteries for the RV power.  They are recharged by a five KV generator.  They are Interstate Batteries.  They were purchased in 2002 and have seen very little use.  I cannot get them to recharge.  I took them into my shop and hooked up my battery charger to them.  While charging, they read 13.1 volts, but as soon as you take the charger off, the voltage starts dropping till it gets down to around 11.9 volts and then it levels off there.  My charger readout says that it is charging them at 9 amps.  It never changes.  As they charge up, the charging amperage should decline until it gets to zero shouldn't it?  Is it possible that both of these batteries has a bad cell in them?  Do you think that if I charge them long enough, they will hold a charge?  Thanks for any help you can provide.    Ron Snyder

Answer
Ron,

Probably not.  Storage batteries can go bad if they are not used over a period of time.
You might be able to get the manufacturer to provide some credit on the purchase of new ones, but you may wish to avoid using the same brand again.
I have had good luck with a Optima battery that is in one of my Toyotas and not used very much. You might want to try that brand.