Problem with battery draining

[ferret1048]

I live at a remote site in Alaska in a class c. I'm having a problem with my battery constantly draining. I use an external Honda 3000 generator for a 3 hour battery charge every day to charge the coach battery, the battery for my cpap and several cell phones and tablets. Once i get everything charged, I disconnect all devices and shut down the generator. I use the water pump for less than 15 minutes the entire day and furnance for about 30 minutes and no lights (it's Alaska and thr sun doesn't set till 11pm). By morning  my battery is dead and I just replaced it. I took it to where I bought it and the checked it out overnight and they said it was ok. When I disconnect my charged battery from the rv I don't get a small spark.so nothing appears to be draining it. In the morning my bettery wont start the furnance. What could be the cause of the battery going dead. Help please.

 

[William52]

You may need an Auto tech to check for a draw 50 miliamps or less is abt. normal more than that is a problem. A glove box light will drain overnight.A bad diode in the alternator can do it also will be warm to the touch. Good luck.

 

[Kevin Means]

Hi ferret1048, welcome to the RVForum. You may indeed have a slight draw on your battery, but if your battery is dying on a daily basis, it's probably not getting a full charge. A 12 volt battery will indicate 12.6 volts when it's fully charged. Don't rely on the cheapo battery meters in most RVs to indicate your battery's State Of Charge (SOC). They're notoriously inaccurate - especially while, or right after the battery is being charged.

Some light duty RV converters have pretty anemic chargers, and it could take some of them nearly a day to fully charge a dead battery. Three hours of charging won't even get close. To determine a battery's true SOC you should use a volt meter or VOM, and wait until the charger has been disconnected for at least 30 minutes, with no loads on the battery. Measuring a battery's voltage while it's being charged, or soon thereafter, will give a false reading... usually too high, because it's seeing residual voltage from the charging process, not the battery's true SOC.

Kev

 

[SkateBoard]

When did Alaska get the internets?

 

[kdbgoat]

What type of battery do you have, and what is it's capacity? If it's a standard automotive battery or a dual purpose marine battery, it may not have enough capacity to get you through a day. Another important thing to look at is it really getting a full charge. Google "Handy Bob" and read his rv battery charging puzzle article. There's a lot of good information there. It's geared towards solar, but the principal of getting the battery fully charged is the same whether from solar, shore power, or generator.

 

[Ernie n Tara]

A single battery is marginal for running a CPAP overnight. Also, the furnace is a power hog so it is not likely to run on a battery that is pretty well dischared.

Ernie

 

[John From Detroit]

First 3 hours is not long enough to FULLY charge a battery, that takes at the minimum 6 and even longer if you have a single stage converter.

Second. as others have said (And this is only partially true) A sligle battery, especially one of the following Group 24, Group 27, Group 29 MARINE/deep cycle is not enough.. (I have seen much much much larger batteries)

Some numbers  For the 3 sizes above you can only use about 25% of their capacity'Group 24, 70-75 AH, group 27 and 29 just under and over 100 AH, Group 31 120-130

Now, a pair of GC-2 Golf car batteries (Six volt in series) make roughly one 12 volt size 4D at 220 AH give or take 10 AH.  But at a lower price and 4 times easier to install.
And now you know why we favor those batteries.