lunchbuckett replied:

Wilankurgab if it is compressor type and the size of the capasitor by my calc it will take 1500 w to start

Keith_A (Qld) replied:

What cable size are you running from the battery to the inverter?

If it needs 500w to start - then at 12V it draws 41 amps.
If the cable length is say 2.5m to your battery, total cable (neg + pos) = 5m
- max voltage loss = 0.36V
0.36 = length x amps x .017 / (cross section wire conductor)
.36 = 5 x 41 x .017 x wire / (cross-section)
Thus Wire cross section = 10sq mm cable.
This is the copper cross sectional area, NOT the automotive size.
Check this website : caravanandmotorhomebooks.com/articles/wiring_woes.htm

If the wiring from the battery to the inverter is too small, the voltage drop at the inverter (at start up of the fridge) would cause the 'low voltage' error'.
Could this be the problem?
regards.................Keith

Geoff (Newcastle, NSW) replied:

What everyone else has said is fair and reasonable.
Another area to look at,
Will the fridge actually run on any Modified Sine Wave Inverter?
It may not have anything to do with voltage drop, starting or inrush current at all.
There's all sorts of sine wave dependent physics going on when you start a split phase motor.

Are you able to beg borrow or generally obtain a Pure Sine Wave in a similar size?
Or just as good a Kipor, Honda or Yamaha inverter style 1kva generator will soon eliminate the problem of Modified v's Pure Sine Waves.

Geoff.

Member - Doug T (QLD) replied:

Wilankurgab
You have to have BEER in the fridge mate

Member - George (WA) replied:

Wilankurgab
Get the battery tested, the voltage may be OK but it may fail under load. I had the same problem as you explained, purchased a new battery, problem solved
Cheers