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Running fridge/freezer on inverter

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Posted by AC/DCdude17 on January 18, 2004, 9:12 am
    We got our share of snow in my area and many people had an outage
lasting quite a while.  I'd like to be able to power a freezer on
inverter powered from car battery for extended outages.  My freezer takes
115W, 145VA to sustain operation, but the compressor is rated at
7.5LRA(locked rotor amps, which you can use to estimate your
fridge/freezer's peak power requirement) and I guess that comes to 900
peak watt.

    The 140W inverter I mainly use for charging digital camera
batteries in my car definitely won't start this freezer, but my
700W(1000W peak) inverter can start it(barely.. it beeps when the freezer
starts).  Is there anyway I can run a freezer/refrigerator on an inverter
short of getting an inverter with a peak wattage that can accomodate 120V
* compressor's LRA?  It's really foolish having to dedicate a 700W(1000W
peak) inverter for a 115W freezer.

Searching the internet showed there's an "easy start kit" that lower's
peak current by starting compressor slowly, but I haven't been able to
find any.

I suppose I could use a series reactor to restrict the starting current
but could the comrpessor start up with restricted starting current?

Posted by Chris Hill on January 18, 2004, 3:36 pm
On Sun, 18 Jan 2004 09:12:36 GMT, AC/DCdude17

You aren't losing much by using the inverter that is properly sized
for the job.  Remember too that the wiring to the inverter must be
properly sized for the job, I suspect that is what your problem really

Posted by ptaylor on January 18, 2004, 10:21 pm
 Chris Hill wrote:

Hmm,I'm slightly suspicious of the wire size too,it sounds like it might
be too small.
I tried to run my PC from my 300W inverter,and it would start
booting,then mysteriously turn off after 2-3 seconds.
After using larger 10AWG wire,and a much shorter run (8-10
inches,instead of 2-3 feet!) I can now run the PC *and* monitor just
fine!  I strapped the inverter to the side of a 12V 17Ah SLA battery I
got for $0 surplus,so it's one nice unit,and I could keep the wires
short.I also made a set of "jumper cables" for it from some heavy wire
and alligator clips,for recharging,tying into the other
batteries,jupstarting the car,etc.Kinda like a homebrew version of one
of those Coleman/Prestone jumpstart power pack things,with a 300W
inverter to boot.It works great!!

Posted by Ray Drouillard on February 13, 2004, 2:45 am

If you have a bunch of snow, why are you worried about your freezer?
Just put all your frozen stuff out on the porch.


Posted by SQLit on January 18, 2004, 4:26 pm

You can buy lots of extra stuff and try to lower the amps or watt
requirement for starting. I will bet that when you discover the cost of the
soft start equipment it would have been cheaper buy a 1000w inverter.  They
are not that expensive.  Besides it will give you something else to run when
the freezer is not. I personally would not be to worried about a freezer
when the temps are low. I had a power outage in Arizona ambient was about
100 F. I did not open it up until the power came back, 2 days. I kept a min
max thermometer in it and it never rose high enough to be in danger.

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