How long should original batteries last?

Photomom

We have a Group 27 Interstate RV/Marine battery, installed by our dealer in May 2016. We have meticulously maintained it, never running it below 12.2v, checking electrolyte level every month during camping season, and storing it in our garage for the winters on a smart charger. 

We are camping right now and it seems like it runs down overnight more than it should according to my calculations. Is this an indication that we should plan to replace it soon? How long do these batteries last under optimal conditions?

elbereth

@Photomom, I don’t know the answer to how long it will last - I think I’ve read in the 5 year range, ideally, but that’s mostly been in comparison with AGMs and lithium which are supposed to last longer.

One thing to check would be to get a hydrometer - around $5-10 from the battery section of your local auto parts store - and check the specific gravity of each cell when your battery is fully charged.  A difference of more than 0.050 between cells suggests you have a bad cell and may need to replace the battery.

Sharon_is_SAM

Found this:  The most common causes of premature battery failure include loss of electrolyte due to heat or overcharging, undercharging, excessive vibration, freezing or extremely high temperatures, and using tap water among other factors.

Have you had to add a lot of water after being on the smart charger all winter?  Suggests overcharging.

Is there any corrosion on your terminals?

Photomom

Sharon_is_SAM said:

Found this:  The most common causes of premature battery failure include loss of electrolyte due to heat or overcharging, undercharging, excessive vibration, freezing or extremely high temperatures, and using tap water among other factors.

Have you had to add a lot of water after being on the smart charger all winter?  Suggests overcharging.

Is there any corrosion on your terminals?

We rarely if ever add any water at all. Terminals are clean. 

ScottG

The group 27 battery I installed in 2016 has a very similar history to yours, and it is starting to do the same thing you describe. It's still doing its job, but some age is showing. I don't think there is a quick answer to the question of how long it will be serviceable.

I did check the specific gravity of the cells this year. They were all the same, but on the low end of the "good" range.

db_cooper

You could try running it through a reconditioning/desulphation cycle if you have access to a battery charger with that function. That might add some lifespan.  If a group 27 is meeting your needs, it would be cheaper to just replace than buy one of those chargers though.

Photomom

db_cooper said:

You could try running it through a reconditioning/desulphation cycle if you have access to a battery charger with that function. That might add some lifespan.  If a group 27 is meeting your needs, it would be cheaper to just replace than buy one of those chargers though.

We were just talking about that. The charger we use in the winter does desulphation so we’ll do that when we get home.