Driving to FL In The Cold

[pisarra@comcast.net]

I recently purchased a 2008 Roadtrek Agile.

I plan to drive to FL in the next few days and plan on staying overnight at Walmart or Flying J. My problem is I do not know how to use my heater and lights during the night without a landline hookup for power. As a matter of fact, the only way I know to get power is to plug in at my campsite.

[wolfe10]

Welcome to the FMCA Forum.

You need to pull out your owners manual and familiarize yourself with your 12 VDC electrical system.

You have two electrical systems: 120 VAC and 12 VDC.

The shore power is 120 VAC, as is your generator.

You have a converter that "converts" 120 VAC to 12 VDC which charges your battery. Your furnace and lights work on 12 VDC.

While driving, your engine's alternator charges the 12 VDC batteries.

You likely have a master disconnect switch for the 12 VDC that needs to be ON when you want to use 12 VDC appliances.

How long the 12 VDC battery (house battery) will power your lights, furnaces, etc depends on the size of the battery(s) and how much power you use from them. The furnace fans take a pretty healthy amount of 12 VDC.

Brett

[pisarra@comcast.net]

OK. I think that I am following you. I can use the inverter to convert from 120 VAC to 12 VDC. The owner's manual says that I have 2 auxiliary batteries (6 volt, Group GC -2 deep cycle leads acid batteries). The owner's manual states that these batteries can be charged by vehicle engine, generator or shore power. My generator is a propane fueled generator. When my RV is not plugged into shore power or generator power, electricity draws from the auxiliary batteries when I use my inverter. Most likely, will the auxiliary batteries last 8/9 hours?

or

Should I use my airconditioner/heater for heat which can be powered by my generator?

[wolfe10]

OK, first an INVERTER takes 12 VDC and "makes" 120 VAC. Said another way, it takes power from your battery and makes "house type current". You may or may not have one. With only two 6 VDC batteries, you don't have a lot of battery capacity to run an inverter.

Your CONVERTER (which you will have) takes 120 VAC from shore power or generator and "makes" 12 VDC.

If dry camping in cold weather, the propane furnace (actually its fan) draws a pretty good amount of current. Depending on ambient temperature, the temperature you set the thermostat on, and your coach's insulation, those two 6 VDC batteries wired in SERIES to make one 12 VDC battery could run the furnace overnight.

And while you could use your A/C (IF, repeat IF it is either a heat pump or has heat strips) off the generator as a heat source, just running the propane furnace is a LOT more efficient. The furnace turns propane into heat. The generator turns propane into RPM's (inefficient) which turns the electrical part of the generator (a little loss of efficiency) which then runs the heat strips or heat pump (another little loss of efficiency).

Brett

[tbutler]

And, if the batteries don't last all night, fire up the generator and recharge them then shut down once they have a charge. In the meantime, while the generator is charging the batteries, you might as well use the heat pump or heat strips in your AC - if you have them. With any furnace or heating system, you have a great deal of control over how often and how long they run to keep you warm. Set the temperature lower and throw on an extra blanket and you may find you can get by all night long with just the batteries.

There are other ways to lighten the load on your heater. Park between a couple of big rigs or on the lee side of a building to shelter you from the wind. If you are parking before dark, get some sunlight in the windshield to help keep the unit warm until dark. If you have a folding sun shade for the front window, use it at night, any insulation you can add will help. We used to fit foam core boards (art department at Wal-Mart) into our windows when we were in a cold location. Windows and leaky seals are your worst enemy when it comes to losing heat so anything you can do to tighten up the air leaks if any and covering windows with even a little insulation will help your furnace run longer on battery power.