Hi Jim,
Mate if the fridge only comes down to +17 C, empty, then it has a big problem. Maybe it needs a re-gas. If the motor/compressor sound OK, as these fridges are fairly quiet, then I think it will be a re-gas.
I have had mine in the tub of a twin cab with a hard lid, on a 43degree day, set on -2 C, and after 4 hours of travel, opened a stubby, out of the fridge, and a few little icicles formed when I took the top off the stubby, perfect temperature.
I have found set at -2 degrees, it will climb to +2 degrees before the compressor starts up again.
The only other thing is that there needs to be some room between items in the fridge so the cold air is able to circulate within the fridge.
Empty on a 31 degree ambient temp day, on 240v, set on 0 degrees C, the.fridge will pull down to 0 degrees in approximately 1/2 an hour, then the compressor will shut off, until the temp goes back up til 3-4 degrees, when the compressor will start again.
If the compressor keeps running, then it needs a re-gas and the sooner the better, as the motor and compressor are not really made to run all the time, IE the duty cycle is not 100%
Let me know how you go
Cheerio,
John

Hi, Thanks for your prompt response. Your answer was the one I suspected, but hoped that it may have been the way I set it up or something else. Thanks again.

Thanks Tracy, I'm now looking at logging power drawn over a few days & will buy a larger solar panel & possibly another 105 ah battery before my next trip. I'm just a little confused as to why my almost new battery is no longer adequate when the same size was in the past.

Hi Stevo normally when a thermostat stops working the compressor will run continuously and the temp will keep dropping below the -3 degrees setpoint. I assume you have done all the standard things like turning it off for half a day then on again and swapping 12v to 240v to see if there is any difference. Other than that I wouldn't know.

Hey hydo no i havnt turned it off for that length of time i’ll give anything a shot thanks

Hi mate, it might be worth checking the condensor ( radiator looking thing fans blow through ) if it is dirty it won't cool the gas and then there is no or little heat transfer which will affect the cooling ability. Blow out with compressed air. Be careful not to damaged the fins. Hope this helps.