Sparky/Fridge Question

Andy, I had a similar problem just recently.
N70ZZ similar vintage, voltage appeared OK (12.6v) but when it was loaded up, RS. Took to battery place and they put their load tester on it and found it was only holding about half its current capabillity. (apparently caused from running down to many times)
If yours is only showing 12.02 I'd hazard a guess it should go to the same place as mine. (Battery Heaven)

Regards

Franga

You need to check the voltage at the fridge when the fridge is running. The voltage may be dropping when under load.

Andy,
This is the Polyfuse problem. Take your fridge to a Waeco service centre and have them change the polyfuse.
Also, remember that the voltage cutout is determined by voltage entering the compressor. If it is showing 12.01 aat the socket by the time it passes through all of the electronics it could be down below 10.5. But my money is on the polyfuse. Mine had the same issue. I bet if you run it on 240v (which is actually a 24v transformer) the problem doesn't happen.

Rob

Thanks for the prompt replies guys.

Think I'll get the battery checked. Might have to do some research on a new battery. (stand-by for battery questions)

Not the poly fuse problem this time Rob, already had that with this fridge, and it still runs on 12v if the voltage is high enough. (I have a second CF50 in the shed with a crook fuse that I need to take in for warranty)

Thanks again, Andy.

does it cut out on low voltage if you try starting it with the vehicle running?...if not then either battery problem or wiring size down to the fridge.

I dont know the start draw on the CF50 but static voltage showing immediately pre fridge connection (no load) can be totally different to voltage under load (amps or current draw)

With the vehicle not running (and your stated voltage indicates that it is not otherwise you would be reading around 13.8V) it is probable that when the fridge starts the current draw loads up the circuit and the voltage drops and the fridge low voltage cut out kicks in...you kind of chase your tail...low voltage available increase amp draw..increases volt drop... and so on

so in summary...vehicle running with no fridge start up problem...vehicle not running start up problem occurrs ...then battery (most likely cause)...wire size may be contributing to the problem

Andy,
Simply stated, the battery you use to power a fridge is stuffed !!

When a 12v battery is 12.02v at rest, it's absolutely less than worthless.

It's probably sulphated to death by being run down to extremely low voltages, as you have nominated 10.5v as the fridge "cut-out" voltage, this is far to low because it causes sulphating with-in the battery and their untimely death.

You say "the fridge runs perfectly at higher voltage" and I suppose you test this by running the engine and charging the 'fridge battery' and then connecting the fridge so it will run from the "charging" battery.
When you turn off the engine the battery drops down to ~12.02v and then the fridge will not run.

I think it's about time to "invest" in a fridge battery that will last more than 2 years and still be working & dependable in 6 or 8 years time, with-out having the problems of holding a charge when being used at lower voltages.

If at all possible I would reset the fridge cut-out to at least 11.5v to avoid damaging any battery in the future when allowing the fridge to run for extended periods of time with-out recharging the battery.