What guage wire for 100w driving lights? (1 Viewer)

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spressomon

spressomon

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OK...I searched and searched but couldn't find an answer: I am going to install 2-100W driving lights on my 100. What guage wire should I use from the relay to the lights?


Thanks,
Dan
 
Distance from the battery-to-relay-to-lights?
 
I am planning to use the factory stalk fog light switch and relay (still need to verify the amp rating of this relay)...I haven't located this relay....assume 6' from relay to lamp?
 
This should help. Use the calculator to figure what gauge wire you need to use to maintain 12 Volts at the lights. Remember P=IV, so P/V=I or 100/12= 8.3333, add 20% for safety and to account for derating due to the higher operating temp under the hood. I would go with 10A.
 
rusty_tlc said:
This should help. Use the calculator to figure what gauge wire you need to use to maintain 12 Volts at the lights. Remember P=IV, so P/V=I or 100/12= 8.3333, add 20% for safety and to account for derating due to the higher operating temp under the hood. I would go with 10A.
Click to expand...





Thanks mucho Dan! Just what I needed.
 
Funny-my seat of the pants response would have been 10 guage! I think 10 guage for short runs can carry close to 60 amps. So a 100 watt light, would draw 100/12== roughly 9 amps, something the 10 guage could carry easily with no risk of resistive heating and the resulting voltage drop.

dclee on this board bought some awesome Bosch relays for a lighting circuit, you might PM him and ask where he got them.
 
Cruiserdrew said:
Funny-my seat of the pants response would have been 10 guage! I think 10 guage for short runs can carry close to 60 amps. So a 100 watt light, would draw 100/12== roughly 9 amps, something the 10 guage could carry easily with no risk of resistive heating and the resulting voltage drop.

dclee on this board bought some awesome Bosch relays for a lighting circuit, you might PM him and ask where he got them.
Click to expand...




Thanks too! I am going to check the factory fog lamp relay to see what it is rated...if I need a new relay I'll PM dclee...I appreciate your info!

Dan
 
I use some Bosch relays from Waytek for my 100w highbeams, at 75amps they are way overkill but have lasted forever in other vehicles and tractors

Waytek #75251 - Bosch #0332002150
 
OK...my Lightforce 170's came today...but the wires that are attached look like 18-guage (if that). And no real way, that I can figure out, of running the 10-guage power supply directly to the bulb sockets.

So will approximately 5" of 18/thin guage make a difference? Or does someone have a 'trick' to accomodate the 10-guage all the way to the bulbs?

Thanks,
Dan
 
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