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Old 11-15-2012, 21:31   #5
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Join Date: Jan 2011
Location: Arizona
Posts: 528
Originally Posted by Contact View Post
Great feedback! If I had to resort to just using the car, my intent would be mainly heat, laundry capabilities and running a fridge. I do own a Kill-a-watt, I'll have to get it going and see what kind of power they draw. As I said, I know they are all energy star rated, but I'm sure the compressor for the fridge kicking on would be more than 800 watts unless my new fridge is significantly better than my old one. IIRC, the old one kicked up to around 1800 starting watts, and then dropped down to around 700 or so, so there'd be no way to use the fridge with any of them. Also, since the furnace is hardwired like usual, it's not like I can plug it into the inverter, so I would have to resort to a room space heater, which uses about 1300 watts while running.

Interesting idea on the high idle circuit...I don't know how easy it would be to do on a newer car that's not wired up for it. It might be easier to get a length of wood to wedge between the pedal and something else to keep the pedal depressed to a set rpm.

Based on what you are describing, you are NO GO.

Forget running a heater off the inverter. You're losing massive amounts of efficiency by changing types of energy - changing heat to mechanical (in the engine), turning mechanical to electrical DC (alternator), turning electrical DC to electrical AC (inverter), and then from electrical AC to heat (electric heater). You are losing probably 95% of the heat energy of gasoline by doing this. It's like going around the block to go next door. You would be WAY more efficient to get a small gasoline burning heater (like one of the old korean war era USGI stoves)

If the fridge draws 1800 starting watts, that's how big of an inverter you'll need. Something like a 1500w continuous / 2000w peak inverter would do the trick. Because the instant you exceed the output of the inverter, it will trip an internal fuse or breaker, and it will put out ZERO until it cools back down enough to reset (or until it is reset manually). And you CANNOT gang up two inverters to handle the load due to phase differences.

Laundry, you could run the washer OK I would bet, but unless you have a gas dryer, you will not be drying laundry (same reason as heater above). There's a reason electric dryers use a 220v plug - because you can't push enough juice through a 120v plug safely to run that kind of wattage.

Most appliances have the "electricity input" tag on them somewhere on the back near the plug. It will say something like "120v at 2.5amps", and from that you can figure out the wattage. The above example would be 300 Watts (120*2.5). That should give you a ballpark idea of what you can run and what you can't.

And don't forget about the duty cycle. Your alternator, putting out 100 useable amps, is only going to be good for about 1200 watts continuous. Go above 1200 watts, and you're going to have a reduced duty cycle.
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