Keeping warm - dry camping

[Chance]

If your batteries are in good shape your plan should work well.

As to battery life, I suggest enjoying their use and figure you'll eventually replace them no different than tires or brakes. Deep cycle batteries should be rated for around 1,000 cycles at your intended use, which is a lot of nights running the furnace. If you replace them yourself when they eventually fail, it may cost $300 to $400 for flooded batteries, which comes out to well under a $1.00 per night.

We all spend so much on RVs, camping, and traveling that battery costs don't seem that high to me. Even if you can extend their life some, the differential savings is minor compared to other costs.

[CC38EL]

The following is just my opinion after 25+ years of doing this.

Straight math calculations for batteries work in controlled environments, with new batteries, and proper charging. Rving in winter is not that.

RV batteries don't fully recharge; the rig has parasitic loads and phantom loads; the fan draw is more than stated.....you get the picture.

If these batteries are the ones that came with the rv when you bought it and they weren't installed brand new in front of you right before you drove off the lot, I guarantee that they were abused. Used until dead or over charged or anything in between. They no longer have the same capability that they had new.

The only true data point is the one that occurs when you run your current plan, measure battery strength at generator off, and then measure battery strenght in the morning before generator on.

Then you will know what you can expect from your setup.

Again....just my opinion. YMMV

[Bob Denman]

"YMMV": Amen!

[jpmihalk]

What CC38EL and Chance state are absolutely true. Temperatures and other parasitic draws affect your battery performance. Therefore, overengineer your solution! If you think you need 200Ah, get 400Ah of batteries... or run your generator twice a day to charge the battery bank and feel safe that you are in good hands. We stay in cold weather often and the furnace doesn't run all night even below freezing, but the load of starting the fan motor is higher than the load when keeping it running and it all adds up over time. Then you need to factor in gas consumption for the genny and LP consumption for the furnace... it is a matter of experimenting to come up with what works best for you!

[Bob Denman]

I agree. The Math might get you "in the ballpark"; but practical experience is what helps you hit the Home Run!

[Chance]

The problem is NEVER the math, it's the person using it. Math is just a tool that can't in itself be wrong.

If you get bad results, you are using "math" wrong or your assumptions are not valid, or more likely incomplete.

What experience buys is the ability to make better assumptions. However, the down side to relying primarily on experience is that it's difficult to apply to a similar yet different problem.

[Steve70605]

Originally Posted by groundpounder

I guess I need to say I would run the generator in the evening to run stuff, and start with a fully charged battery. Once I go to bed everything is basically off except for the heater. My calculation 77 amps was if the fan ran all night, worse case. In reality it would go on and off as needed to keep the coach warm. My real guess is maybe 20-30% or about 2-3 hours overnight. Now we are talking about only 23ah or 11% of the battery capacity. In the morning the generator comes on (wife wants coffee). I think there is a 50 amp charger so a recharge happens in an hour with coffee.

There seems to be no way the batteries don't hold up over night.

Our coach is 38' overall length with 4 slides. We routinely dry camp and stop in rest areas / cracker barrels. This past winter we camped in 16 degree weather while traveling. We stopped the generator at 9:00PM. We run 2 propane heaters, residential fridge, CPAP all night. Temperature set to 67 degrees inside coach. Generator is set to autostart at 11.9 volts. Have 4 6V batteries in bank. Voltage is usually about 12.1 to 12.2 in AM (7:00)

Depending on number and type of batteries should not be an issue. (FWIW - Harris batteries that come with coach are junk. I replaced mine with much better units)

[Bob Denman]

"The problem is NEVER the math, it's the person using it. Math is just a tool that can't in itself be wrong.

If you get bad results, you are using "math" wrong or your assumptions are not valid, or more likely incomplete. "


You can obtain a Math answer, that may or may not be the complete answer...
Experience helps you to focus on the larger picture!

[Bob Denman]

Originally Posted by Steve70605

Depending on number and type of batteries should not be an issue. (FWIW - Harris batteries that come with coach are junk. I replaced mine with much better units)

What did you replace them with??

[Steve70605]

Originally Posted by Bob Denman

What did you replace them with??

Interstate GC2-ECL-UTL (4 ea)

6Volts

447 Reserve Capacity (RC)@25 Amps

225 Amp Hours (AH)@20 Hr

12 Months Free Replacement Warranty

Extreme Cycl

Not advocating these but seem to be much better than the Harris batteries I had......

[Bob Denman]

http://www.thorforums.com/forums/att...1&d=1519081356

That's EXACTLY the info I was looking for...