bulb draw?
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Post Fiend
Joined: May 2006
Posts: 10,007
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From: Central Florida
bulb draw?
I am working on the 05 superduty headlight conversion. I bought Mertipack 150 connectors and was curious how hot they might get. The bulbs had 0.4 and 0.6ohm resistances. As I figure it, the bulb can draw 30 amps, is that right or do they have another property that screws up ohms law? 30 amps would make for 260 watts. These are marked 60 watt so the amperage should be 5 amp. There was no change in resistance with the terminals on the pins, so I don't think I will have much trouble with them heating up.
Junior User
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Good Site To Check Out The Electronics Club Resisters If Lamps Are In Parelll Ohms Will Be .24. At12v 2amps Also Check Transistors On Site They Have Your Battery Charger Onemore Site To Check Battle Bots Iq Fixed Magnet Dc Moters Pg 2 Shows Checking Moters W Ohm Meter Aqand Using Ohms Law
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Post Fiend
Joined: May 2006
Posts: 10,007
Likes: 4
From: Central Florida
I don't know what happened. The bulbs aren't hooked up. I was curious if there was induction or something else that caused the ohm reading to be off. I expected the resistance to be closer to 2.4 ohms rather than 0.4 ohms.
Cranky Old Guy
Joined: Mar 2008
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From: Raphine, Virginia
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Post Fiend
Joined: May 2006
Posts: 10,007
Likes: 4
From: Central Florida
I was only working on one. My relay harness will have a 15 amp fuse, as I plan to use Piaa Bulbs and they might draw a little more current than they let on.
I learneded ohms law in schoolin once. Thanks for the link though. The way I learned it was a little easier.
E=I*R and then P=I*E. A little substitution can give you any variant and if you put it in a circle the we had it in school, it is really simple to make the formula work with out substitution.
I learneded ohms law in schoolin once. Thanks for the link though. The way I learned it was a little easier.
E=I*R and then P=I*E. A little substitution can give you any variant and if you put it in a circle the we had it in school, it is really simple to make the formula work with out substitution.
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From: Virginia
There is a snag on reading the resistance of a lamp. A hot filament has a different resistance than a cold one. It's also well known that incandescent bulbs and also heating elements with filaments have a current surge when they are first turned on, and the filaments are cold.
So you are safe to go by the wattage of the bulb, though if that's been measured at 12 volts, and you soup the wiring up so you have around 13 or 14 volts at the bulbs, their wattage and output will increase a little bit, and their life will be shortened a little bit. This is a small price to pay for more light though.
So you are safe to go by the wattage of the bulb, though if that's been measured at 12 volts, and you soup the wiring up so you have around 13 or 14 volts at the bulbs, their wattage and output will increase a little bit, and their life will be shortened a little bit. This is a small price to pay for more light though.
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