question

luderick avatar image
luderick asked

Should I use a larger inverter, or smaller dedicated ones?

I have a motorhome - i am contemplating, should I have a dedicated say 300W inverted for my fridge (my only 24/7 load) or should I not worry and just have one larger inverter. what are the losses when the load is only say 40W - thanks

Multiplus-IImultiple inverters
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4 Answers
snoobler avatar image
snoobler answered ·

Considerations:


  1. Higher power inverters have higher self-consumption, i.e., they consume power by converter DC to AC even if there are no AC loads.
  2. Loads may have a surge. A compressor motor is a good example. Surge can easily be 5X as high as the run current/power.
  3. Based on charts I've seen, inverters are at their peak efficiency around 30% of rated.
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seb71 avatar image
seb71 answered ·

Can't you keep everything DC?

There are DC fridges.

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scubadoo avatar image
scubadoo answered ·

We have a motorhome here in NZ and have been travelling fulltime for 8 years.

Our NZ$700 255l Samsung 230VAC digital inverter fridge has been powered by a dedicated $100 300W PSW inverter mounted behind the fridge and has remained unseen for all those years and still performing perfectly. It draws about 500mA @ 13V idling.

There is no surge on start up unlike the typical standard mains powered fridge without that "digital inverter" technology.

We have a seperate 1000W PSW inverter to power the toaster etc. etc. that is powered as required,



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Thanks and that is what I’m considering- I guess I can see how it goes with one inverter and if I’m not happy instal a small dedicated inverter


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Kevin Windrem avatar image
Kevin Windrem answered ·

A small inverter MAY be the right answer but look at the idle power specs carefully. I have a Multi Compact 2000 VA inverter for my travel trailer with an idle power of about 9 watts and considered a smaller inverter to run the TV. I could not find a say 500 watt inverter that used much less idle power than the Multi Compact. The inverter mentioned by scubadoo uses 6.5 watts at idle so it's better by a little. You'll have to shop around to see what's best for your situation.

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