Wiring a replacement 12v fridge

[mikewroe]

After much discussion I have bought an Alpicool CR90X, collecting it today. This is to replace our old 3 way fridge.
From memory I believe the max current draw is 6 amps. I require about 3m of cable to run from the LB to the fridge, please could someone advise to best size cable to use.
Already wired is the existing 12v supply to the old 3 way, albeit only powered when the engine is running. As this is relay switched, is there any reason why I can piggy back onto this. This way I have the benefit of a poor mans B2B system?

 

[wildebus]

After much discussion I have bought an Alpicool CR90X, collecting it today. This is to replace our old 3 way fridge.
From memory I believe the max current draw is 6 amps. I require about 3m of cable to run from the LB to the fridge, please could someone advise to best size cable to use.

It is not the draw when running you need to account for, but the surge when the compressor starts.
I have seen lots of installs where the installer based the cable on the running current and found the fridge only worked when the battery was full.
Basically, the compressor surge (can be 10 x the running current) will cause a voltage sag and if the cable is too thin, the voltage drops low enough for the fridge to think there is a low battery issue and will not start.
3 Metre run I would get 10mm2 cable I think. And for both +ve and -ve.

Already wired is the existing 12v supply to the old 3 way, albeit only powered when the engine is running. As this is relay switched, is there any reason why I can piggy back onto this. This way I have the benefit of a poor mans B2B system?

Depends on the cable fitted. A three way fridge 12V element is no more than 200W maximum (with no surges in this case) and if they fitted cable only good enough for that kind of use, you might find the maximum safe current could be 20A or less. Could be a bit low for battery charging and you might find the fuse just blows?

 

[Exwindsurfer]

Mine is about 3m run to fridge and yes I use 10mm2 cable as well .

 

[mikewroe]

Thanks everyone, 10mm it will be.