hry avatar image
hry asked

Phoenix 12|800 Inverter - surge / peak / spike protection or smoothing for refrigerator?


I have a setup running a Phoenix 12/800. It is all running very nicely with one issue:

We have a very small (43L) Ikea fridge/freezer which uses only about 30W continuous power when on. The problem is, when it cycles to ON (ie compressor kicks in), it demands such a peak that the inverter jumps into the red zone of the meter (bluetooth app) for about half a second before coming way back down to 30W. In this time the inverter is clearly struggling and the lights dim etc! While plugged in, the fridge cycles on/off once every 5-10 minutes. Naturally we have now disconnected the fridge.

  • Is there some utility to 'absorb' / 'smooth' this peak as not to stress the inverter so much? Will a surge protector do this, or just turn off?
  • Are there fridges with smoother / softer peaks, or is this a universal issue?

FYI: Battery bank is 3x 280Ah 12V, with 35mm2 wire connecting. Wire from battery bank to inverter is 25mm2, which i believe is the largest you can fit into the connectors on the inverter housing.

Update: some have recommended soft start modules, if anyone can recommend a specific unit I would be grateful!

Many thanks for any input!


Phoenix Invertermodificationspeak
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2 Answers
kevgermany avatar image
kevgermany answered ·

It's common, most motors do this.

a look for soft start modules. They plug into the socket and the fridge plugs into the module.

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hry avatar image hry commented ·
Many thanks for the suggestion, Kev, I will look into those. Any specific recommendations you have used?
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Nev avatar image
Nev answered ·

Surge currents can be a real issue and are apparently often much higher than anticipated.

Inverters vary enormously in their peak surge versus time capabilities.

A few years ago I had a 70l 100W rated "bar" fridge in our motorhome.

A quality 600W inverter could never start the compressor while a 800W would start it with some effort but it would stall about once a week requiring a restart. A 1200W inverter was neccessary for 100% reliability.

I experimented with several "soft start" devices and Googled circuitry with no improvement - ever. Others hopefully have more success. Try before you buy would be wise.

By contrast our much larger 255l Samsung fridge with a digital inverter compressor has now survived 8 years of fulltime travel powered by a dedicated 300W PSW inverter running 24/7.

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Related Resources

Phoenix Inverter product page

Phoenix Inverter Smart product page

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