headlights 6v? 12v?

[used red MN]

but reading comprehension is suspect.

 

[47fivewindow]

Wire the two bulbs In series and hook to 12 volts. If they seem bright enough they are six volt. I had so many 6v bulbs I wired a few tractors that way after up grade to 12v They will both go out if one fails. Good trick for the next generation though.

 

[Brokengun]

More than likely those are 6 volt bulbs.

By a resistor similar to what Chrysler used on their cars and trucks back in the 1970's or use the resistor that Case used for the 930 Gas tractor that went to the to the coil. Run a wire in line before the Bulbs and they should be ok

 

[BarnyardEngineering]

"Plug them into 12V and see if they blow up" is NOT a valid bench test. It completely defeats the purpose, which is to USE the lights!

If you're going to intentionally destroy them, why not just hit them with a hammer then order new ones so you know what you've got? Cut out the middle man. Save the hassle of finding wires and a 12V source.

Yeah, it's funny and cute and all that. Ha ha ha. Still NOT an answer to the question.

 

[Ericp351]

Seriously? Why all the 'Showcroppy" answers? Masure Resistance -R. Assume 30 Watts. V=I R. Watts = I * V. This Example: 30W = 6 (volts) A. 30/6 = 5 A. V = I R . 6 = 5 R. Thus : 6/5 about = ohms IF 6 Volt. If off by a factor of 2- probably 12 V, et cetera! This is grammar school stuff. EDIT! I didn't see / read "Jim in ME's" excellent response. If I did I'd have saved the typing thing (try to help, ain't no chick). Rock on Mr Jim.

 

[TN 2N]

I would find a bulb of known voltage rating, maybe from another vehicle, and measure the ohms. Then measure the ohms of the unknown bulbs and compare.

 

[Janicholson]

I would find a bulb of known voltage rating, maybe from another vehicle, and measure the ohms. Then measure the ohms of the unknown bulbs and compare.

Ohms can be the same on either voltage if the watts change. so the comparison only works with two bulbs of the same wattage. Jim

 

[Ericp351]

Yes, in theory. In real world-and as stated, above- these are more or less 30-35Watt sealed beams. Even 15% variance is completely tolerable as the 12V ohms vs. 6V is TWO To One ratio. Here "close enough" is good enough. Far short of rocket science.

 

[Hemmjo]

It is important to note here, that light bulbs do not follow OHM's law as you might expect!

While light bulbs do exhibit a relationship between voltage, current, and resistance, their behavior is not strictly linear like that of a resistor. This is because light bulbs are nonlinear devices whose resistance changes with temperature.

Also off road bulbs will have different readings that automotive bulbs because the elements have to be more sturdy to withstand the bouncing around they get off road.

Connecting the bulbs in series is a good way to test for 6volt vs 12volt. Two 12 volt bulbs in series will be very dim.