1940 Ford Deluxe Voltmeter for 12 Volts
 

I am changing my 1940 Ford Deluxe from 6 to 12 volts. This year car uses a volt meter rather than an ammeter. I can not use a RUNTZ 12volt to 6 volt reducer for this voltmeter. Called Don Baxter about alternatives. He said he had no alternative for my standard voltmeter. Does anyone have an alternative keeping the same appearance voltmeter or do I need to change all my gauges in my instrument panel? :confused:

Re: 1940 Ford Deluxe Voltmeter for 12 Volts
 

Since you worked with elevators, you must be familiar with electricity so all you need is a series resistor at the meter plus terminal. The value of the resistor can be calculated by ohms law and a few measurments but may be much easier to determine by trial or a 10 turn helipot.

Re: 1940 Ford Deluxe Voltmeter for 12 Volts
 

Yep. A 55 to 60 ohm resistor in series with the meter will work. I used a 10 watt rated resistor on the pickup. It has a deluxe gauge panel.

Re: 1940 Ford Deluxe Voltmeter for 12 Volts
 

A place like Williamsons in Arkansas may be able to recalibrate your original gauge to work with 12 volts.

Re: 1940 Ford Deluxe Voltmeter for 12 Volts
 

I had Williamsons in Arkansas rebuild my gauges 25 years ago. He put a resister in line with the volt meter, and it works great. I used a voltage reducer on the rest of the gauges.
Dave

Re: 1940 Ford Deluxe Voltmeter for 12 Volts
 

I used a variable resistor to set the gauge at the top of the red bar with just the ignition switch on, I started the car and watched to see if the gauge went into the green band, it did. Then I turned on all the lights and the heater to see if the gauge went into the yellow band, it did. Then I measured the resistance of the variable resistor to see how many ohms it was, I then bought a resistor of that value and installed it on one of the gauge leads and It always worked perfect. Good luck

Re: 1940 Ford Deluxe Voltmeter for 12 Volts
 

I used a 7W 60 ohm Wirewound Resistor that I bought from West Florida Components on a 39 Deluxe.
Check out the info from Flat Ernie in this thread: http://www.fordbarn.com/forum/showthread.php?t=142104&highlight=12+converting

Re: 1940 Ford Deluxe Voltmeter for 12 Volts
 

Re: 1940 Ford Deluxe Voltmeter for 12 Volts
 

Dah on my part. Thanks for the all the responses. It is appreciated and makes sense. Glad you guys out there with experience can really help.

Re: 1940 Ford Deluxe Voltmeter for 12 Volts
 

I THINK if you measure the resistance of the volt meter and get a resistor
of that value and parallel the resistor with the volt meter it will read half
the voltage. G.M.

Re: 1940 Ford Deluxe Voltmeter for 12 Volts
 

Replies such as these plus input from guys like Bubba and Uncle Max in their fields
of expertise are worth...............how much...........can't put a price on it. Thank you
Ryan for keeping this site afloat !!
Charlie ny
'Ol Ron, G.M., Walt Dupont, Mac Van Pelt to add just a few more

Re: 1940 Ford Deluxe Voltmeter for 12 Volts
 

If it were not for guys like those named by Charlie ny, and many others who have helped this neophyte out on many occasions, I would just be driving modern iron, which is not half the fun. Thanks for all the help received on the Barn, from "All Y'all". Lawson

Re: 1940 Ford Deluxe Voltmeter for 12 Volts
 

Apols for digging up an old thread, but I have to ask: why can't you use an isolated solid state converter for the voltmeter?

My understanding is the solid state units simply provide a consistent 6V drop across them regardless of load.

I'm not questioning the logic of the resistor - what am I missing?

Re: 1940 Ford Deluxe Voltmeter for 12 Volts
 

I think your understanding of modern electronics is a bit higher that the average of the members here. Sounds like a good idea, though; they're cheap enough these days. If it was me, I'd get one and try it.

Re: 1940 Ford Deluxe Voltmeter for 12 Volts
 

I'll give it a whirl and report. It might be a while - it's a friends car I'm wiring.

Re: 1940 Ford Deluxe Voltmeter for 12 Volts
 

Isn't the solid state units attempting to maintain a consistent 6v? Doesn't that defeat the purpose of a voltmeter? You are wanting to see the variations in voltage, not look at a meter showing you a constant reading as the voltage varies. Once the voltage dropped below some level it would not be able to correct for it, but what you end up with is an idiot light, on or off.

Re: 1940 Ford Deluxe Voltmeter for 12 Volts
 

I think I see your point. If your 12V system drops to say 10V, the 6V meter will 'see' 4V.

Dropping to 8V, the 6V meter will 'see' 2V. Not exactly linear indication. More like a good/bad indication - idiot light.

Once the 12V system drops below say 6v, there will be nothing on the meter, but of course by this time the situation is code brown anyhow.

Re: 1940 Ford Deluxe Voltmeter for 12 Volts
 

Use the 60 ohm resistor, it's proven to work well...