I finally remembered what I was going to ask about earlier.

Most of us have inverters in our cars, so we should be able to power a small electric blanket or large hot pad. Which one is more efficient:

-running the car every so often to recharge the battery a little bit, then turn it off and stay with the battery?
-running the car every so often to reheat an entire cabin full of air?

I'm not talking anythign huge, just like a crib warmer or something. Put it under you in the car seat, with a blanket over you. Turn the electric on for say 15 minutes every hour. Or will it draw too much charge off the battery?

Well, that depends how many amps the blanket will draw. In colder weather, I think it's harder for the battery to work at its maximum efficiency, so I'd be tempted to err on the safe side and run the car longer than normal. I mean to say, I'd be less likely to use the blanket while the engine was off.

The wife has one of these blankets. Its a bit larger than you are describing. The thing is awesome but it takes a bit of time to reach a good level of heat. I actually saw some small heater fans that are designed to be plugged into a cig lighter of a car. They blow a surprising amount of hot air, but seem to burn up a lot of power. At my fav outdoor store, they actually sell electric socks, which are battery powered believe it or not. I got a pair for bow hunting for those times when you have to remain in place for long periods. These things are the warmest socks I have ever worn in winter. I wonder if they make battery operated blankets as well??? Like you said, if you run the engine for a while to warm the blanket, even every second or third time you use it, then you will spare the battery for when you need it most.

12-volt electric blanket
-Blast

I think I might be tempted to take a good car battery, on its own, and see how long it'll run the blanket before it dies. That would at least give an idea of what to expect.

You could, but I'm not sure that's a good idea. As I understand it, a standard car battery can suffer permanent damage, or have its service life reduced, by a severe discharge. Most inverters cut out at around 10.6 volts DC to prevent this.

Why not just carry a full size duvet? You are in a car; youv'e room.
The Sock

I'm with you on this one. I would carry adequate warmies that are non electrical. I wouldn't want to depend on a car battery for something as vital as warmth - keep it for starting the car.

I also agree. Using an electric blanket assumes that you will have the vehicle and power. If you have to leave the vehicle for any reason, the electric blanket isn’t going to help you much.

I would only recommend the idea if you equip the vehicle with duel batteries. This is a standard set up many 4 wheelers use. High draw and most acessories draw from the second battery. Then rvrn if the battery gets too low the primary battery is used to start the vehicle which in turn recharges both.

http://www.heatedcarblanket.com/?gclid=CJ-Cqr7nqpACFRY0sgodxBQDMA
http://www.heatedcarblanket.com/?gclid=CJ-Cqr7nqpACFRY0sgodxBQDMA






12 Volt Auxiliary Heaters & Fans that plug into the cigarette lighter to defrost the Windshield with warm air or for instant warmth in a small concentrated area. 12 Volt Heaters are limited in power because of the maximum current draw that is available from the cigarette lighter socket and will only produce warm and not hot air. The larger heaters (Direct Battery Hook-up) are able to warm a small area such as a truck cab and need to be directly wired to the Battery or a 12, 24 volt high current (30A+) source at the fuse box.

Selection of fleece electric heated blankets that get power from the vehicle's cigarette lighter plug. 12 Volt blankets get warm and not hot like the 120 volt Blankets.


Great idea but the 12VDC electric blankets and space heaters only put out warm air/heat not like a conventional electric blankets and space heaters. You would probably have to use a 110v one to do the job but you would need a much larger inverter and your battery would probably not make it. You could get a cheap battery at wallyworld for that purpose but as much money you would be spending a good sleeping bag would do better for that case. We always carry 2 bags while traveling in case we do break down. We almost broke down one winter while going west on I-26 in South Carolina going to ashville and it was snowing. Fortunately I got the truck running on 7 out of 8 cylinders (Ford F-150) and it got me there.I was just about ready to start digging in and set up camp when I finally got it working. The ole lady was yelling at me the whole time. No cell phone coverage or nothing within a long long way.

I use heavy wool blankets. Whenever you feel a little too cold, turn the engine on and let it run for 10-12 minutes. Don't worry about specific amounts of minutes and stuff. YMMV