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
asked
Should I use a larger inverter, or smaller dedicated ones?
Considerations:
- Higher power inverters have higher self-consumption, i.e., they consume power by converter DC to AC even if there are no AC loads.
- Loads may have a surge. A compressor motor is a good example. Surge can easily be 5X as high as the run current/power.
- Based on charts I've seen, inverters are at their peak efficiency around 30% of rated.
Can't you keep everything DC?
There are DC fridges.
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,
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.
