Coach Batteries Not Holding a Charge

[JimSpy]

Our 2017 Gemini has about 15,000 miles on it, 8000 since we picked it up used, and our coach batteries no longer seem to be able to hold a charge. They charge up full from AC, from the engine battery, and from the generator, but turn off the charging source and they drop back to near-empty within a minute or two.

Is this the normal lifetime? Do I need to replace them? Anything special I need to know about them?

Extra Credit: Is this situation a threat to any of the systems, such as the on-demand hot water heater? Does it need a spark or something, or does anything require continuous current? Reason I ask is, when I first come aboard after the battery has been discharged for a while, I hear an alarm or a beep from the back of the coach. I assumed this was the water heater telling me it needed LPG, but maybe it needs a current also? I just don't want any explosions in my driveway, thank you.

[JimSpy]

Originally Posted by JimSpy

Is this situation a threat to any of the systems, such as the on-demand hot water heater? Does it need a spark or something, or does anything require continuous current? Reason I ask is, when I first come aboard after the battery has been discharged for a while, I hear an alarm or a beep from the back of the coach. I assumed this was the water heater telling me it needed LPG, but maybe it needs a current also? I just don't want any explosions in my driveway, thank you.

Well, duh, if it can alarm, it's got a current, porridge-for-brains!

[Sweetbriar]

Since you acquired the rig used only the past owners/users know how the batteries were treated. Run them down into the 10VDC range or below constantly and service life will get very short. Boiled them dry a fews times and you're well on the way to replacements.

What to get depends on how you use the coach. Heavy off the grid boondocking maybe something lithium based or AGS is in your future. Occasional weekend on the beach then a couple of Costco or Sam's Club golf cart 6VDC types will do the trick. If 99.99% of your outings are at full service campgrounds then a basic car battery will work.

Extra Credit - Without DC pretty much nothing works. Not necessarily damaging to installed systems or creating a hazardous situation. Worst case might be the quart container of cottage cheese in the fridge or the half gallon of melting ice cream in the now warm freezer going off and smell that is somewhat difficult to get rid off. The alarms could be any number of things and my guess would be the propane and/or carbon monoxide detectors coming back on line.

[The Gritz Carlton]

Bought mine in May 2018 and already see a drop in the original capacity. Res fridge used to go nearly 48 hours on batteries...now it barely goes over 24. These batteries are taxed with the up and down cycles and two years is about all you can expect from them. Batteries are pretty cheap...cold beer is priceless.

[Bob Denman]

Without knowing how the prior owners treated the batteries: it sure is possible that they took a fatal hit...
It's time to replace them.

[nosticks]

Batteries shot. Only take a surface charge then rapidly decline. New battery time.

[Popfla]

That beeping sound is very likely the CO detector. My previous rig did that when the house battery was getting low. Served as a good reminder for me to either crank up the genny or plug 'er in for a while to top off the battery.

Sounds like you're in the market for new batteries.

[Bob Denman]

Do you have Girard tankless hot water system? If you don't have it up and running: it might be a low water pressure alarm...
(Ours used to do that.)

[JimSpy]

Originally Posted by Bob Denman

Do you have Girard tankless hot water system? If you don't have it up and running: it might be a low water pressure alarm...
(Ours used to do that.)

Well, it's been 4 years, but I think I remember that that WAS the problem. So belated thanks!