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Testing Headlight Bulbs Indoors.

5K views 8 replies 4 participants last post by  Kspec01 
#1 ·
Hello everyone, I dont know if this is the right place for this, but anyways my question is as follows : How can I test H7 halogen bulbs indoors? Ive tried this before simply by tring to use a battery and connecting one side + and - to the other. It does not work, as soon as I take it to the car, and plug it in, it all works :confused:


The reason I need to perform this indoors is I'm redesigning some glare shields for HID's that I had previously installed, my previous mistake was that I needed the headlight housing to be lit while I cut & bend the shield to minimize the glare. Now I have some time to get to this ( being the 4th of july weekend and all) and I really would like to get this completed. Please give me any good advice onto getting the bulbs to turn on without being conncected directly to the car. Thanks in advance to whoever response!
 
#3 ·
yevRPS said:
you said you're using the battery....is the output 12v?
Yep, tested it with a DVM. Think I may have to blow the dust off some old college Electronic books and see how to test bulbs :(


Anyone else wanna please give me ideas/advice on how to this?
 
#4 · (Edited)
There must be enough juice (amps) in the battery to run the lamps... remember, each bulb draws approximately 55 watts of power at 12 vdc... or about 4.5 amps.

However, if you're using a strong enough battery or pack of 8 "C" or "D" cells in series, it should light the bulb if all your wiring is conducting electricity.

The polarity (+/-) doesn't matter for incandescent (filament) bulbs like headlights; it only matters where a diode is being used (LED lights and such).

If you're using a 12 VDC power source, and if the bulb works in your car after not working inside, then you've got a problem in your test rig's wriring / connections somewhere...

It's really a simple loop circuit; you shouldn't have to look it up.
 
#5 ·
kylemorg said:
There must be enough juice (amps) in the battery to run the lamps... remember, each bulb draws approximately 55 watts of power at 12 vdc... or about 4.5 amps.

However, if you're using a strong enough battery or pack of 8 "C" or "D" cells in series, it should light the bulb if all your wiring is conducting electricity.

The polarity (+/-) doesn't matter for incandescent (filament) bulbs like headlights; it only matters where a diode is being used (LED lights and such).

If you're using a 12 VDC power source, and if the bulb works in your car after not working inside, then you've got a problem in your test rig's wriring / connections somewhere...

It's really a simple loop circuit; you shouldn't have to look it up.
Thanks, I will try another battery or an alternate power source to see if its that then.
 
#6 · (Edited)
I'm not going to get into extreme details because of the danger of electricity, but I will suggest that if you have a knack for electonics you can build a 'test power supply' out of an old computer power supply. Computer drives run on 12vdc.
 
#7 ·
hyunelan2 said:
I'm not going to get into extreme details because of the danger of electricity, but I will suggest that if you have a knack for electonics you can build a 'test power supply' out of an old computer power supply. Computer drives run on 12vdc.

HHHM good point :thumbsup: I actually have a few powersupplies laying around in my room, I will try using that if another battery does not work. Thanks alot! :clap:
 
#8 ·
If you use a computer power supply, you'll have to find a way to trigger the "voltage good" (I think it's called) feedback loop that's supposed to go to the motherboard. I did that years ago to run a car CD player into my home stereo (when I was younger and poorer, had a car CD player I wasn't using, and couldn't afford a home CD player).

If you do tinker with a computer power supply, do not take the metal case of the power supply apart. There are capacitors in there that can shock, burn, or even potentially electrocute you if conditions are right. All the connections you need are on the wires that are supposed to go to the inside of the computer.
 
#9 ·
Thanks guys everything worked, but now i burned out one of my ballast :( need a replacement. anyone know where I can buy a McCulloch ballast?
 
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