The AC output of automotive inverters should be good enough for that.
The usual automotive inverter output is what they call a "modified sine
wave", which is more like a "modified square wave". The RMS value of the
output is 120 VAC or reasonably close. The waveform goes like 3/8 cycle
positive, 1/8 cycle zero, 3/8 cycle negative, 1/8 cycle zero.
The RMS voltage of the 60 Hz (or fundamental frequency) component alone
will be a little short of 120 VAC (or tal RMS voltage), and lamps that use
ballasts may run a little dim. Motors will be not quite full blast and
may give noisier vibrations from the harmonics but will basically work,
and should not have trouble unless they barely work with true sine 60 Hz
full 120 VAC. I imagine a motor will heat up a little more with the
different waveform with "slightly wrong" RMS voltage of fundamental
frequency compinent alone, although this should only be a big deal if the
design or condition of the motor and/or the equipment using it is already
DISCLAIMER - NO WARRANTY BY ME, especially for monetary amounts in
excess of fees that I get from you for making this post. :)
- Don Klipstein ( firstname.lastname@example.org)
On 18 Feb 2004 13:53:31 -0800, email@example.com (JW) wrote:
I've been using a setup just as you describe quite reliably for the last 3
years. It's a DC inverter rated at 1500W (peak 2100W). You can find one for
under $200 if you shop around. Mine comes with 3 A/C outlets on it and I just
use one to backfeed my service panel through an unused 220 dryer outlet. I
just select the circuits that I deem "necessary" and have no problem during
On the car side, you'll need beefy cables that connect from the car battery to
the inverter. #4 or larger for this size inverter. They can be a pain to
work with, but you will be maxing out the battery under full load and need
them. My alternator is 130A, so I have no problem keeping up with full load.
I suspect you can get away easily with a 90A one - but not much smaller.
On the house side, I take the 110 from the inverter in to a 220V plug that has
the 110 hot crossing both 220 hots. The neutral and ground remain normal.
Throw ALL breakers in the main panel and connect the plugs. Now, turn on 1
breaker at a time for where you want service and you should be fine.
My main concerns are heat and the fridge when we lose power. My inverter
keeps up with these things plus a few lights and small TV just fine.
Make sure your car is running when you try to use anything with a small start
load. If not, the inverter will draw too much juice and fail to start the
appliance due to lack of input power from the car.
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