does anyone that logs onto this board know whether an ampmeter can be converted to a volt meter? any help or information is greatly appreciated.
Yes, and no. Both use D'Arsonvall movement that convert very tiny currents into a magnetic field that moves the needles. First of all, your ammeter will be set to be center zero, and you want your voltmeter to be zeroed at the side (you will not be reading negative voltages; the ammeter is set up to show both the amount of current and the direction it is flowing). Secondly, an ammeter has a shunt in parallel with the windings so that if, say, 30 amps are flowing through the circuit, the coil only sees the few milliamps (thousandths of an amp) it needs to register. Otherwise the winding burns out. You can change the range of an ammeter by changing the value of the shunt. Voltmeters on the other hand have a series resistance to protect the coil since you want to have a voltage divider effect where the voltage across the coil is the very few millivolts that, combined with the internal resistance of the coil provide the few milliamps for the needle to move. An ideal voltmeter appears as an infinite resistance so that it does not load down the circuit it is attempting to measure. So it can be done but you need to change both the physical (center off) and electrical (shunts/resistance) to make it work. This is probably not worth the effort. You are better off just replacing the guts of the ammeter with the guts of a voltmeter.
I do not believe that a conversion using and amp gauge to read voltage levels is possible. A few years ago a guy who I was building a small block mopar for his ******* had told me he was sending his dash cluster out to have the ammeter "converted" to a volt meter. I think the company name was redwire or redline or something like that. When the cluster came back I took a good look at it to see if I could see what they had done to accomplish this....the removed the ammeter mechaicals and replaced them with a VDO volt gauge hidden inside of the ammeter case in the backside of the gauge cluster! It appeared that the other gauges had had the needles all freshly painted and cleand so it all matched when you looked at it from the front. So I'd say this is probably the only solution to a "coversion" from amps to volts.
Most auto ammeters are direct reading for high current, which means they are a short circuit. If you try to measure voltage, it will smoke the meter (or melt the wiring, or whatever is the weak link in the circuit). Some ammeters are different, they are used with an external "shunt" and measure the voltage across a short section of wire. They are too sensitive to be used to measure 12v, but might be converted by someone who knows what they're doing.
Let me take a stab at that - an ammeter is connected in series with the circuit being measured. A voltmeter is connected across the place you want to measure voltage, usually the positive battery terminal and ground. The ideal ammeter has an internal resistance of zero, so it does not load down the circuit. Remember, there is a shunt in parallel in there. The ideal volt mater has an internal resistance of infinity, so 'no' current flows through it and it does not load the circuit. So what happens if you connect a device with an almost zero internal resistance (an ammeter) from hot to ground? AKA short circuit, my friend, and that ammeter for a very brief fraction of a second will be heating your shop.
Both an amp meter and a volt meter are really measuring amps. So is an ****og electric temp gauge. It's the current flowing through a wire (amps) that create the magnetic field that moves the needle. If you start there yes it should be possible to recalibrate an amp meter to read volts. If you have an old ****og multimeter, all it's doing when you turn the switch is change the way the probes are connected to the meter, and add or subtract some shunts or resisters and key to a different scale on the meter. My advice though would be to replace the gauge. Since you have to redo the face to read volts already, starting with a fresh volt gauge would be far less trouble.
I would'nt try and do it as voltmeters are quite inexpensive as are ampmeters. They each measure different readings. Current is measured in amps and voltage is measured in volts. An ampmeter is used to measure direction of current flow while a voltmeter measures voltage in a circuit. If you want to be real cool, put both in your dash. No reason why it can't be done if you are buying gauges to install.
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