4 replies to this topic

[sonny]

I have a sunpro ammeter gauge in my dash, which i wish to connect. i already have the bulb wired in so when the ignition is on the backlight is on. Yesterday i tried to connect the ammeter up. I earthed the dial from the -ve on the back of the gauge and used a wire which has power when the ignition is on (Power source i use for the backlight on the gauge). i turned the ignition on then just touched the +ve of the gauge to the power source, and it basically got VERY hot very quickly and instantly began to melt and burn the wire and plastic case around the wires on both the earth and power source wire coming from the gauge. so i obviously removed the wire very quickly and all was well again except from the fact that i still dont have the ammeter working.
I have since read on google that it may just be the fact that i was using too thinner too higher gauge wire , and by using thicker lower gauge electrical wire it may be ok.

Help please

thanks a lot,

sonny.

[Pooky]

Sounds like you're doing it wrong. I had a TIM ammeter. It connected in series between the alternator and starter motor.

to be honest it's a pretty boring, useless gauge. It's also not very safe bringing the high current circuit into the cabin. If you haven't got one already, fit a voltmeter instead. Otherwise leave it disconnected.

[Dan]

STOP - DO NOT DO ANY MORE ELECTRICAL WORK.

What you did is very, very dangerous. Frankly you are lucky you still have a car, that could very easily have developed into a massive electrical fire.

The gauge is an ammeter, not a voltmeter. You CANNOT short it directly accross the battery, which is effectively what you did. It's nothing to do with the gauge of the wire, it's simply an electrical principle. An ammeter measures current, in order to do that it is essentially a dead short. A voltmeter is quite the opposite, it has a massive resistance and is meant to be shorted across wherever you are measuring a voltage. Ammeters measure the current flowing in a circuit, if the circuit you put it into is simply a piece of wire the current will be enormous.

The electrical system of your car is dangerous if messed about with. I'm not against people working on their cars at all, that's why we are here but the fact that you did this suggests you have little idea about how electrical systems actually work. I suggest you read some books and do some research, including from the advice available here, before you do any more electrical work. This isn't meant as a dig at you, but dangerous work needs to be pointed out. I'd no more let someone carry out dangerous modifications to their brakes.

Ammeters are essentially pointless in cars fitted with alternators, all it will really do is tell you if the engine is running or not. The wiring required to fit them (at least the type most car gauge companies seem to want to make) is potentially very dangerous. If the gauge ever develops a fault, the car's whole electrical system will be cut off.

The ammeter has to be put in line between the battery and the car's whole system, except for the starter. In a Mini this is a little trickier than in other cars, it means running a single very large cable from the solenoid, through the bulkhead to the gauge and another back to the solenoid. All the electrical power in the car will run through this cable and if a short to the body develops on it, the car will almost certainly go up in flames. What is the range of the ammeter you have? They tend to be +/- 30A which is no use at all.

It is dangerous if fitted badly but if you really want it, then we can give you full instructions on how to do it safely. It's a lot of work for a gauge that will pretty much do nothing though.

[wardyxxx]

Ditto to what Dan said!!!!!

Get a voltmeter instead.

[cooperrodeo]

I wouldn't bother with a voltmeter either, if you have a decent alternator.