Farmall Cub

I have a 12 volt with alternator that I want to replace the amp meter with a voltmeter. What is the preferred and neatest method of wiring the voltmeter. It of course will fit the same hole in dash as the amp meter. The old amp gauge has two wires on the + terminal and one on the minus one. Do I simply stack the three wires on the plus terminal of voltmeter and the minus terminal to ground? Not a lot of room for three wires on the tiny positive post of new voltmeter. But I can make it work.

Your thoughts please.

Your suggestion would be the easiest thing to do. Other than rewiring (to avoid joints in the wiring) I cant thing of any feasible way to redo it, since ampmeters and voltmeters function in two totally different ways. All you need to make a voltmeter work is voltage from any + and -.

Initial thought on how to wire the volt meter will cause a parasitic drain, running down the battery when tractor is not running. The volt meter needs to be switched off when the tractor is not running. Place between the ignition switch and ignition coil.

http://www.the12volt.com/installbay/for ... ?TID=15196

Edit: The wires on the amp meter must be spliced together or rewired from the alternator to the battery terminal lug.

Eugene wrote:Initial thought on how to wire the volt meter will cause a parasitic drain, running down the battery when tractor is not running. The volt meter needs to be switched off when the tractor is not running. Place between the ignition switch and ignition coil.

http://www.the12volt.com/installbay/for ... ?TID=15196

Edit: The wires on the amp meter must be spliced together or rewired from the alternator to the battery terminal lug.

Good point....didnt even consider the drain on the battery.

Need to check again, not home now, but I am pretty sure that the power to the original amp meter is switched. Don't believe that a battery drain would be a problem with ignition off.

BIGHOSS wrote:Need to check again, not home now, but I am pretty sure that the power to the original amp meter is switched. Don't believe that a battery drain would be a problem with ignition off.

The regulator diodes inside the alternator is the switch, preventing battery drain when tractor is not running. If the tractor had a generator and cutout or regulator, the cut out is the switch disconnecting the battery from the generator.

Your initial plan provides an alternate path for current from the battery to ground. The volt meter has to be installed after a switch, not before a switch.

As long as you wire it in where the meter drops to zero with the switch off, you'll be ok.