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I am building an 'Off Grid' tiny home, with my primary energy supply from solar + battery storage. I intend to utilise low voltage everything possible with the exception of a standard home washing machine and a chest freezer converted to chest refrigerator, which I intend to power via inverter.

  • Is using inverters in this way an efficient use of power, and will I run into reliability issues with either the appliance or inverter? (or does this come down to purchasing quality products?)
  • Also, what rating inverter should I purchase with respect to the rated draw of the appliance? (I am aware these appliances have high startup current.)
LShaver
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zxspectrum
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  • Why not DC refrigerator and washer? – paparazzo Jan 23 '18 at 14:46
  • @Paparazzi I suspect because these are harder to find and more expensive -- a quick search on a swap site for the medium city where I live gives 10 results for chest freezers for under $200. A converted freezer will also tend to have better insulation, meaning it will run less often. – LShaver Jan 23 '18 at 15:11
  • @LShaver It is also more efficient. I would like to get a response from the OP. – paparazzo Jan 23 '18 at 15:13
  • Thanks for your replies, here in New Zealand the 12 volt versions of these appliances are very expensive and not readily available. The models that are available are generally very small and intended for occasional use in an RV. As this will be my home I would like full size, reliable brand products for a reasonable price. – zxspectrum Jan 23 '18 at 16:26
  • That's some good detail to add to the question. Also, roughly what size freezer are you looking for? – LShaver Jan 23 '18 at 17:20
  • I keep 2 refrigerators in my home. One in the garage that I use in the winter and one in the kitchen that I use the rest of the year. Since the garage is uninsulated and cold in the winter, we save on electrical power. – 0tyranny0poverty Feb 22 '18 at 00:13

1 Answers1

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Searching for small- to medium-sized chest freezers on Home Depot I found that GE provides details on current draw for 5 cubic foot and 7 cubic foot models (140 and 200 liters, respectively).

In their wiring recommendations, the manuals specify a 15 or 20 amp breaker (at 115 volts). Thus we can assume that the maximum current draw for either is under 15 amps.

Inverters are typically provided with a maximum power rating. To satisfy a peak of 15A at 115V, your inverter will need to supply 1725 watts:

 V   *  I  =   P
115V * 15A = 1725W

Since you'll also have a washer, you'd want to have a bit of overage designed into the system. You could easily do with a 2000W inverter, such as this one: 2000-Watt 12-Volt Off-Grid Pure-Sine Wave Battery Inverter.

LShaver
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  • Thanks, this is helpful and does indeed help with my second question. My understanding was that a chest fridge made from a freezer was very efficient, and It would indeed be around the 5 to 7 cubic foot I would use. I would perhaps use a separate inverter for each appliance. I would still ask if this setup would generally be considered reliable and efficient. Thanks for your time. – zxspectrum Jan 24 '18 at 07:37