Not Enough Juice! (Need Help with Coach Battery)

Some things that I have not seen mentioned in this thread.

You should never discharge your battery more than half its amp hour rating. So, if your battery is 80 amp hours then you only get to use 40 amp hours.

My furnace blower uses 7 amps. 40 amp hours divided by 7 amps is only 5.7 hours of use. And this is assuming that your battery is fairly new, that it is fully charged, and that the furnace is the only thing being used. Obviously, a forced air furnace is not very useful for off-grid camping. If you do use it, you would be better off running the generator, turning on the heat and warming up the RV, then turning off the heat and generator. This would be way more efficient than charging the battery and using it to run the furnace.

Of course the RV is going to get cold at night, so you will need to sleep with a good down comforter or sleeping bag. As other posters have said insulating your RV will also help. You can add thermal window covers and a thermal curtain blocking off the cab area.

You mentioned switching to two 6v AGM batteries. All the 12v AGM batteries I have seen have about half the amp hours of a lead acid battery. So using two 12v AGM batteries in parallel would only give you about the same amp hours as one lead acid battery.

If I remember correctly, putting batteries in series does not increase the amp hours. I just looked at a couple of 6v AGM deep cycle batteries. They seem to have about 200 amp hours, so in series they will have the same 200 amp hour rating. This will be slightly more than double your current battery.

Depending on your RV's converter, running the generator to charge the batteries may be an issue. Older RV's like mine only put out 3amps to the charging circuit. It takes forever to charge a battery at 3 amps. Most newer ones put out more but you need to check yours and also see if it has 3-stage charging. Without 3-stage charging your batteries will not be fully charged and will wear out sooner.

Well, I could go on and on, but there are lots of threads on these topics already on the forum--just search for them.

Here are some more links that should be of interest.

Articles about RV electrical systems:

BATTERIES--AND OTHER ELECTRIC STUFF

The 12v Side of Life

Intro to Dry Camping

Battery Education