amp gauge

Ammeters work in "series" ie they are placed in the cable between the battery and the Fridge.
I would cut the +ve wire coming from the battery and connect to term 1 and the other wire going to the fridge on term 2.
Where you do this is another story but that is the basics
Iam a 240v electrician and that is the way I would do it on my vehicle.

Hi Undertaker,

If you want to install an ampmeter in your vehicle, you should install it using three wires, so that you can measure the charge rate and discharge rate assuming you have a center zero meter.

Assuming you have two batteries and an isolator of some type, all you have to do is chop into the main wire between the isolator and the auxillary battery and wire terminal 1 or + to the dead side of the isolator along with the wire to your fridge. Then wire terminal 2 or - to the auxillary battery.

This way you can see if your auxillary battery is getting charged and by turning off the motor and opening the isolator, you can see how much the fridge is drawing. One thing to remember is that if you have a 30 amp meter you must at least use 30 amp cable.

Personally I wouldn't put an amp meter inside the vehicle. If you must have one, mount it near the auxillary battery under the bonnet. I'm only saying this because I've seen a few cars burn because of amp meters...Valiants were bad for it.

Good Luck

Chaz
http://members.bettanet.net.au/~conody/index.htm

Hi,

If it is one of the common automotive ameters that reads 30-0-30 or 60-0-60 and you want to use it to see your fridge power consumption, don't waste your time.
The meter deflection will be barely noticable when the fridge is running.
Cheers

Hi TheUndertaker, another idea would be to get a cheap amp meter of about 10 amp reading and just put it in the wire going to the fridge.
The is also a small clamp device that is used as an add on for a normal multi meter. You could set this clamp up at the existing battery cable or fridge cable and the run some wire from the clamp to a multi meter set up in the cab. Not a great set up as a permanent fixture but it is a good set up that lets you easily check different wires all over the vehicle without having to cut any of them.
Cheers

Be cautious with ammeters.

These must be wired in series with whatever you need to measure. No problem if you can mount and still read the meter without extending the wiring - but if you need to extend cabling you will increase the voltage drop.

If you really must do this - follow the advice to use a so-called current shunt. This is connected in series with a main battery cable and a pair of thin wires go the a voltmeter (that is calibrated in amps). With is setup distance does not matter.

Forget the 0-30-0 meter idea. These things are wildy inaccurate and it would barely move at all with a fridge's typical 2.0 -3.5 amp draw.
Collyn Rivers