Coach battery health indicators.

 Our 2010 2551 came with little history. It's two Lifeline 100Ah 12v AGM batteries are of unknown age, at least 3 years old, likely more as the elderly owners had been unable to do upkeep, it appeared, when we bought it on consignment.

It has a Blue Sky Solar charge controller and display. The display can cycle thru many indicators: input, output, voltage, battery capacity, etc.

Battery capacity had always been 100% after any manner of charging until lately. Now I can only get it up to 70% or so, either solar or shore power, or stand-alone battery charger.

I'm assuming this means the amperage is only 70%, and therefore the batteries are weakening?  I hope it is just time to replace them, if this is what is indicated.

I'm easily confused when it comes to electricity. I view it as magic, as no logic appears to be involved.

Thanks

Dougn

Dougn,

If possible, disconnect the Lifelines, put them on a small charger/conditioner such as a Battery Tender.    Leave them on the battery tender for a couple of days, hook them back up and see what it says the charge is.

If it's still 70%,then yes, it's likely the Lifelines have simply "worn out" and they should be replaced.

Don

I agree with Don's advise.  Disconnect the batteries and charge them conventionally using a typical battery charger and then see what is learned.  AGM batteries in general will last longer than 3 years.

My personal experience with two different pairs of standard 12V wet acid batteries, each pair gave us 2 good years and one marginal year.  Year number 4 was always a train wreck.  I installed our 3rd pair of batteries in April 2015, but they are 6V AGMs and are still very healthy.  Keep in-mind our rig stayed hibernated all of last year and continues to this day.  I do put them on a 4 amp charge every 3 months to keep them alive and well.

We are setup conventionally.  No solar or other fancy charging setup.  With the current pair of 6V AGM batteries, I also installed a volt meter in an easy to read place in the rig as a constant reminder when it is time to charge.  I try to avoid dropping below 12.1V when under load which is usually at night with the lights on.  Next morning is charging time with the generator.

Please note that % charge has nothing to do with the state of battery charge or amperage per se. There is a shunt in neutral wire. The Blue sky monitors how much current goes in and how much goes out. If there is more current going out then going in, either from solar array or your 120v converter it will be low.

Try charging with a charger like they say but do not disconnect any of the cables or the % charge will not record correctly.

There is a way to reset this number, see Blue Sky's manual.

I did charge it overnight with my trickle charger, disconnected nothing but the shore power. Went back to 100% and 12.9v. Now in the full sun it is 14.2v and holding 100%. Something must have been stuck as this is what I had done previous days with no improvement in percentage, and nothing running.

Should I switch off the batteries and see how they hold with no load?

I'll have to keep my fingers crossed...

Thanks for all the help, and I need to study the Blue Sky manual more.

Should I switch off the batteries and see how they hold with no load?

No, I would just see how the%charge holds up when you are not charging and have a load.
Probably fine, unless the batteries were mistreated.