Need some battery advice!

[Powerstroke2000]

I'm currently having had an issue with my Interstate 12V (dual) batteries in my Arctic Fox camper, in that after 3 days of boon docking, my fridge stopped working, thus realizing I must be below 6 volts of power (was told the fridge needs 6V to run while on propane). After the 3 days we where back on the road, so the truck charged the batteries to the point where the fridge would run fine, and after that we stopped where we would have shore power for the few nights prior to heading home.

I did pull my batteries and put them in my garage on a piece of carpet and my 4 stage charger started out showing 25% power in the battery, and within a half hour it was up to 100%. I'm unsure if this is a true 100%, or if the charger has been fooled in some way, as it didn't take long to get to where it should have been. I say this, as I put this same charger on my wife's car, where she was having no battery issue, but when I put it on it showed her battery at 50% and it took overnight and into the late morning before 100% showed. My charger breaks down the sulfation process, but whether the battery is at a true 100% I don't know on this camper battery. I have another 12V interstate (currently in the camper which I'll change out with the charged one) and see how long that one takes as well. I think these batteries are about 5+ years old, but we're thinking of perhaps going to a motorhome, so I don't know if it's worth spending the $$ to change them out, or if a full charge and maintenance through the winter (if it didn't sell) is worth it?

[2oldman]

Powerstroke2000 wrote:
thus realizing I must be below 6 volts of power (was told the fridge needs 6V to run while on propane).

I did pull my batteries and put them in my garage on a piece of carpet

You were told wrong, and you should be carrying a voltmeter.

Why did you mention a piece of carpet?

[Yeti_plus]

Take both batteries to a battery place and get them to load test the batteries. A load test will let you know if they are good or not.
Canadian Tire usually has a load tester in the automotive parts department, which is okay if the attendant knows how to use the tester.
You should also check water levels in both batteries, might get lucky and just have to add some distilled water.
Brian

[Lwiddis]

"thus realizing I must be below 6 volts of power (was told the fridge needs 6V to run while on propane)."

Oh my. Read RV battery basics on line. Nothing in a RV is 6 volts except a battery by itself. But one 6 volt without a companion never happens. They are hooked in series. RVing since 1980? Must be a misprint.

[KD4UPL]

The charger has no way of knowing the state of charge of your battery. It can really only look at voltage which doesn't mean much unless it's been at rest for at least 24 hours. I'm guessing you can't program the charger for the battery size so it doesn't really know what charge rate it's giving the battery. The "so called" state of charge is largely marketing.
If you got 3 days of boondocking out of a set of batteries I'd say that's not too bad depending on your usage patterns. Batteries that are 5+ years old are nearing the end of their useful life. Depending on how well they were cared for they might be done but since you got 3 days I'd say they are decent yet.

[donn0128]

RVs need 12VDC to work. If you had 6VDC you have at least three cells shorted or something else going on