Battery/fridge query

[driward]

Hi,

Looking for some advice please.

I want to have a small 12v fridge which runs most of the time while I'm driving about but I want it to cut out so that it doesn't run while I'm parked during the day or overnight so it doesn't run down the battery. As long as it runs for short periods while I'm driving I'll be happy.

I thought I'd try and tap-in to an existing automatic shut-off (the radio, which comes on automatically on ignition and shuts down when engine is off) so I've tried powering it from the cables supplying the radio head unit - hoping that when the ignition and radio are off it would also knock off the fridge, but for some reason the cables won't power the fridge.

Is there any other way of having an automatic shut-off to protect the battery? If there's a solution I'd ideally want to do the same with my inverter so it cuts out when not using the vehicle.

Many thanks

Dan

[g8dhe]

The normal system would have a leisure battery installed and the fridge would be running from that, A compressor fridge will run from a 100AmpHour LB for about 2-3 days.
Never seen an installation as you describe but you could wire it to the Ancillaries supply which is ignition switch controlled, along with the radio, I suspect maybe you have wired into the wrong radio supply there are two supplies to the radio one un-switched which stores the radio settings, the other controlled via the ignition switch for the main power. The ancillaries also feeds the 12v cig. sockets around the van.

[driward]

Thanks for your reply. It’s strange because my voltmeter shows something like 11v coming from the switched live behind the radio, yet when I connect any device to it, it doesn’t work…anyway I’ll try and do as you suggest and connect it to the Ancillaries supply. Do you know where I’d find that by any chance? Thanks again

[g8dhe]

If your only getting 11v then the fridge will probably not work anyway as they have a low voltage cutout to avoid flattening batteries. You maybe need to find out why your only getting 11 volts, start by checking at the battery terminals themselves, then after the battery clamps and then down at the fuse block. You would expect at least 12.6v from a fully charged battery.

[driward]

Thanks for your help on this: I used the wires feeding the cigarette lighter and it works perfectly! Only a matter of time before I end up begging for tips again