One of the batteries died

[HiHoAgRV]

I have 3 group 27 interstate batteries just over a year old, a multi stage charger and a Trimetric system...

The trailer spent a week in the drive, no power draw except phantom loads and no shore power...

I noticed the Trimetric showed I was down to 80% so I plugged in and checked the water levels...the front mounted battery was low so I topped it off...the other 2 were fine...

The next day, Trimetric shows charged to 180%!!!...the front battery is too hot to touch...other two...fine...

Question...

Replace the one bad battery?

Comments...if I had not noticed the Trimetric, I'm sure I would have baked all of the batteries...I've done it several times before...that's why I'm not a big fan of the "2 12's are better that 2 6's cause if a 12 dies you still have 1 left..."... Not for long!

[Phoenix]

We have a marine battery isolator switch and use it to charge (and use) our two batteries separately. That way, if one goes bad, the other fully charged battery can be accessed by just turning the selector dial. See details in the link below, and other similar threads on this site:

http://www.airforums.com/forums/f368...ml#post1031945

[HiHoAgRV]

Thanks Phoenix, I guess I didn't state my exact concern...2 batteries used and one new goes against the common thought that all of them should be the same age...just looking for some thoughts on that issue...

[Phoenix]

We replaced our OEM batteries as they failed, one year apart; so one blue top is one year newer than the other one. One recently failed, which oddly enough was the newer one; so it looks like they will never be in synch as to age. The age of the OEM batteries when they failed were 1 year old, and two years old. The blue top was four years old at failure, and the remaining one (still in use) is five years old.

We charge and use only one battery at a time, so the difference in battery ages is moot. Rarely, we have used both simultaneously when both have been partially discharged; and we were trying to stretch the time before recharging them.