Coach batteries toasted?

I can run my furnace all night in 20F weather and have power left in the morning. I do set the temp to 60/65 during sleeping time. The coach batteries are two 12 volt deep cycle batteries.

oyly wrote:


It's a 2014 Winnebago Via. Think it has two batteries, and these have been well drained a few times.

This says a lot. A recipe for battery failure.

If you are not sure how many and what type and size of batteries you have then it is pretty obvious that you have not been checking them regularly and have likely suffered at least somewhat from under or over charging. "well down" makes me assume you mean more than 50% (12.2 volts). True deep cycle batteries can take some very deep discharges with some loss of life.

Find out what batteries you have, what shape they are in now (SG etc) and what charger or converter you have.

Learn as much as a you can about the care and feeding of lead acid batteries.

Then you should get many years out of you batteries.

Don't feel bad about not having treated you batteries well, I would suspect that many if not most on this forum have done the same in the past and/or are still doing so.

I killed 4 group 24s by a season of chronic undercharging then almost killed the replacement 4 6V GCs when the power went off for an unknown period of time with both roof fans running. They seem to have recovered relatively well, only time will tell.

So has the water level been checked in them since RV was bought. Probably not since number of batteries seem to be unknown. :(

oyly wrote:
Can't run the cabin heater through the night without draining the batteries down. Seems very strange that it would need so much power. Should only be the electric fan that needs the electric power?

Anybody have similar experiences?

to answer your question assuming you 1)have sufficient battery power and 2)you know there top notch shape and 3)were previous to this charged fully then the RV lpg furnace should not deplete the batterys over the course of a nite (10) hours

OK, so I've found out that I have two group 24 deep cycle batteries. 12V and 80Ah each. If like scrubjaysnest writes, I can only use 50% of that capacity, then 80 Ah / 10 A (worst case?) = 8 hours of running time for the fan.

So even in perfect condition, the batteries would just barely last the whole night. I'm surprised, seems like the system is under dimensioned. Will definitely check the SG and possibly install some extra batteries as well.

Only once....dry camping in a Wal-mart parking lot on a 20 degree nite did i go this route. (Without the generator) After 7 hours...the fan still worked..but seemed weak(er) than earlier in the evening. No matter...the V-10 started just fine and that began the re-charging of the 2 6V coach batteries.
I might have "gotten-outta-there" just in time. But..for 7 hours, it worked.

My thoughts:
I do not believe they make group 24 'deep cycle' batteries. I'm sure you have marine 'hybrid' batteries.

From your comments I'll suspect you have neglected your batteries. If so, they will never return to maximum, like new capacity no matter what you do. I seriously doubt they can still provide close to 80Ah/charge.

Now that you better understand the importance of proper battery maintenance it may be prudent of you to start over with new batteries and see if you can protect them better. A pair of group 27's would be better than the 24's but you may need more. Do a power audit to determine your real world needs. Do you have room for bigger batteries? I don't. Can you properly maintain and charge a bigger pair?

Not knowing your camping style this could be delayed to a later date. Do you foresee relying on them to supply maximum potential in the near future?

FWIW: I neglected my first battery when I was learning. I never paid any attention to it until it started to fail after about two years of use. Now I equalize them every three months, top off with water when needed and they can last for at least 6 years or longer. The question is do you want to put in the effort to maintain them for longevity or just replace them every few years as needed?

2112: Interesting question. My gasser motorhome, bought new in 2001, gets around 3 years out of any conventional battery (6V or 12V) most any brand....from Interstate to Sams' Club. (BTW, now using DEKA)

Doesn't seem to matter.

So I found out my batteries are NAPA 8240. 24DCM:

http://www.napaonline.com/Catalog/CatalogItemDetail.aspx/Battery-Deep-Cycle-12-Wet/_/R-NBD8240_0213748540

Seems you were right 2112, they're not real deep-cycle batteries. The label says "Marine/RV Dual Purpose". NAPA also doesn't state the Ah rating, which I've learned, is typical for non-deep-cycle batteries. But to estimate the Ah rating, some say divide the reserve capacity by 2. That gives me an Ah of just 70.

Been looking for a user manual for these batteries, but can't find any. The one in my Winnebago manual also doesn't say anything about checking the SG. So I'm not sure if I'm able to! There seems to be two lids on top of the batteries, but prying them off was harder than what seems normal, so I'm worried I'll break something if I try harder...



Also started looking into bigger batteries. I would have to make some modifications to the tray where the batteries sit, as this was clearly made for exactly group 24 batteries. As for a more powerful battery in the same size; Seems they all have about the same amount of power, 140 A reserve capacity.

Did anyone reading this increase the battery capacity in their RV? How did you do it?

A furnace suck alot of power. Most RV manufacturers dont plan people to run the furnace at night. Our 5th wheel came with a single 12 volt battery. It wouldn't pass 2 hours of furnace when dry camping. I upgraded to a second 12 volt, but also installed 4 - 300 ah batteries in the front compartment for my inverter. I installed a battery switch and could switch to these.