Low Batteriies

[Koladog]

This is the third winter storing our trailer plugged into shore power in our driveway. I noticed the other day that our battery meter read 11.7V (or 41%). Have I fried my batteries? Or can they still be saved if I took them out and connected a trickle charger to it? Just wondering. Thanks.

[cw3jason]

3 years on a battery is not bad for life expectancy. have you checked your electolite level?

[Koladog]

3 years of limited use is not bad? This RV thing sounds like an expensive adventure. Anyways, we when bought the trailer the dealer said we have maintenance-free batteries that are completely sealed. As a matter of fact, the batteries are encased in a hard plastic box which doesn't look easy to open up. Long story short, no, I haven't check the electrolyte level - didn't think I need to (if I can at all).

[RdRmr]

Koladog,
Just an FYI, in my many years of RVing I have found leaving your rig connected to shore power constantly while stored will kill your batteries faster than usual. I plug it in for eight - twelve hours then unplug it for a week or when the charge is at 50% or less. It seems that exercising them helps them last longer. Over the years this has worked for me.
Happy Campin....

[Koladog]

Thanks RdRmr.

That's good to know. Learn something new all the time. I will heed your advice going forward.

[bobbecky]

You don't say what your rig is or what year. If it's not very old, you might have a converter that has circuitry that maintains the batteries. On our rig, the converter is made by Progressive Dynamics, and has their Charge Wizard that cycles through a battery maintenance scheme that allows the rig to be plugged in indefinitely without harm to the batteries. There are other brands that can do the same thing. You might take the batteries out and have them checked. You may have lost one, even though they are fairly new.

[dcg9381]

Just an FYI, in my many years of RVing I have found leaving your rig connected to shore power constantly while stored will kill your batteries faster than usual. I plug it in for eight - twelve hours then unplug it for a week or when the charge is at 50% or less. It seems that exercising them helps them last longer. Over the years this has worked for me.


I found this to be true with chargers that didn't float and hard-charged. Although modern chargers are known to be "smarter" than old ones - I assume they are not until they prove otherwise. I monitor voltage across a couple of days to see what the charger is doing.. The above way is probably a bit of insurance.

Koladog - if you're at 11.7v while plugged in, something is wrong. Check the water level, report back.

[Koladog]

It's a 2013 Mountaineer. Don't know the make/model of the converter. I'll have to check later when the weather is cooperating. Sounds like I'll have to pull the batteries out also.

[cw3jason]

Most RVs do not come with sealed AGM batteries. The dealer usually throws in the cheapest batteries they can find. I would open your battery box and see what you actually have installed.

[JRTJH]

Your first post indicates that you have "more than one battery". If this is true, are they both the same size/brand/age? If not, therein may lie your problem. 12 VDC batteries must be "equal" to effectively charge, otherwise, the "weaker" battery will "control" the charge status and draw down the "stronger" battery. Also, one "bad cell" on a battery will affect the charge capability of the entire battery bank.

So, if you have two batteries, one came with the trailer and you added another, if it wasn't done "at the same time" (or nearly the same time) that may be your problem, or if you've got one "GP 24 battery" and one "GP 27 battery" that also may be your problem.

Your RV probably came standard with a WFCO Power Center. In 2013, the charger in WFCO products was a "smart charger" and would go into "trickle charge" or "maintenance mode" once the batteries were charged.

People "full time" in all kinds of RV's, Montana is a prime "full time rig" and people leave them "plugged in" 24/7/365 without any adverse problems with their batteries.

My guess is that you've got either "mismatched batteries" or a battery with a "bad cell". Pull your batteries, take them to AutoZone or a similar type store and have them load tested. Then you'll know what you're dealing with.

Remember that if you do have a bad battery, you'll need to replace both to maintain a reliable battery system.

[Koladog]

Thanks for info JRTJH.
My invoice says I have two interstate 6V batteries but of course I've never opened up the box to see what was actually inside. The box is big enough to store 2 batteries.

More and more it sounds like one bad cell. I'll pull the batteries out this weekend and have them tested. Thanks for all the good comments and advice. Will provide an update once all is sorted out.

[Festus2]

Thanks for info JRTJH.
My invoice says I have two interstate 6V batteries but of course I've never opened up the box to see what was actually inside.
.

If you haven't "opened up the {battery} box to see what was actually inside" since you purchased your RV in 2013 then your batteries are long overdue for an inspection - particularly the water levels. The battery terminals and cable ends should also be checked for corrosion.

If you haven't checked the levels and have never added water, it could be that one or more of the cells in each battery are dry.

[JRTJH]

Festus2 "hit the nail on the head" with his advice. If you haven't ever opened the box to see what's inside, it would indicate that you've never done any battery maintenance.

The battery electrolyte level (water level) should be checked at least monthly, even more often in a hot, dry climate. The cables should be checked for corrosion and to be sure they are tightly connected during each "fluid check".... If you haven't been doing this on a regular basis, there's really no way to know if your batteries are still "salvageable" or not.

At this point, I'd pull the cover on the battery box, check the electrolyte level, fill each cell with distilled water to the "internal ring" and hope that you've got to them in time.... If they function, you'll be very fortunate. Chances are you'll be buying new batteries in the very near future. When you do get new ones, set a schedule to check them monthly. Your wallet will appreciate your efforts <wink> :)

[Koladog]

So it was a case of low water. I filled up the cells with de-ionized water, hooked it up to my battery tender and in a couple of days it was holding a good charge again. I'll let it sit for a few days (unhooked) and check the charge again. Maybe I saved it in time?

[jsmith948]

If you do end up needing batteries, Costco sells Interstate 6v golf cart batteries for $90 each. That is assuming you have Costco stores in BC. I hope you dodged the bullet, but, it has been my experience that, once a battery has gone dry to the point that the plates are exposed, it is usually toast. Good luck.