Fridge voltage

[Portia]

I have an eldiss affinity 554 .does anyone know what amps is required to power fridge when towing.sometimes it works and sometimes it doesn't. I was told I need a stronger relay but I need to know what amps before I choose relay

 

[Damian]

Depending on the wattage of the heating element it will be between 8 and 10 Amps

 

[Woodentop]

It is most likely that the voltage sensing relay (in the rear of the car) that switches the power on to the fridge (and the habitation relay) when connected to the car needs adjustment. A bit of Googling will explain how to do it - takes minutes with a small screwdriver.

 

[BryanTheSnail]

Going back to the relay point, auto relays would easily cope with the load, and if overloaded would burn out, thereafter not work at all, not intermitantly.
You could test out the switching relay if that is how you car is wired by checking caravan fridge feed voltage which will be zero with engine stopped, and rise to 13 volts ish with engine running at about 1500 rpm. .

 

[Woodentop]

Going back to the relay point, auto relays would easily cope with the load, and if overloaded would burn out, thereafter not work at all, not intermitantly.
You could test out the switching relay if that is how you car is wired by checking caravan fridge feed voltage which will be zero with engine stopped, and rise to 13 volts ish with engine running at about 1500 rpm. .

Well, not quite. Once the ignition warning light has extinguished the alternator is charging - it does not require a lift of revs like a dynamo did.

 

[BryanTheSnail]

True, but giving a figure does mean that the OP will have an idea of what should happen.. Had I not suggested an rpm value he could have just started the engine and left on tickover, with indeterminate results.

 

[ChrisUK]

Last time had this problem I measured the volts at the car battery with the engine running, then measured the fridge volts. There was a big volt drop. To make the drop reasonably I had to increase the cable size and fit a better relay. I used to have an Electrolux chart / curve of cooling against volts and a volt or two can make a big difference.

 

[chrisn7]

It is most likely that the voltage sensing relay (in the rear of the car) that switches the power on to the fridge (and the habitation relay) when connected to the car needs adjustment. A bit of Googling will explain how to do it - takes minutes with a small screwdriver.

Yes, this is the place to start before getting involved with cable sizes, which should be adequate anyway on a modern installation.