55w driving lights on a 35w circuit |
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55w driving lights on a 35w circuit |
72 IXXIV |
Jan 7 2018, 11:23 AM
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#1
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Member Group: Members Posts: 62 Joined: 1-January 15 From: San Francisco Member No.: 18,277 Region Association: Northern California |
I’m considering replacing my stock 35w fog lights with a couple h3 55w halogens as has been described on the forum. Is that too much load for the wiring, or is it within the margin of error?
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Elliot Cannon |
Jan 7 2018, 11:29 AM
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#2
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914 Guru Group: Retired Members Posts: 8,487 Joined: 29-December 06 From: Paso Robles Ca. (Central coast) Member No.: 7,407 Region Association: None |
I’m considering replacing my stock 35w fog lights with a couple h3 55w halogens as has been described on the forum. Is that too much load for the wiring, or is it within the margin of error? Give it a try, then find the origin of the smoke. (IMG:style_emoticons/default/laugh.gif) |
mihai914 |
Jan 7 2018, 11:41 AM
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#3
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Senior Member Group: Members Posts: 800 Joined: 2-March 05 From: Montreal, QC Member No.: 3,697 Region Association: None |
That's 157%
Heat buildup in the housings will be an issue also and will probably affect the wiring first. Have you considered LEDs? |
Mueller |
Jan 7 2018, 12:12 PM
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#4
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914 Freak! Group: Members Posts: 17,146 Joined: 4-January 03 From: Antioch, CA Member No.: 87 Region Association: None |
Use a relay, the stock wiring can activate the coil.
Run new wire just for the power. |
914Sixer |
Jan 7 2018, 12:17 PM
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#5
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914 Guru Group: Members Posts: 8,845 Joined: 17-January 05 From: San Angelo Texas Member No.: 3,457 Region Association: Southwest Region |
I wonder what the factory did different on the 75-76 foglights. They came with h3 55 watt bulbs in the assembly. The wiring should be the same except for the different lights. Also the European Driving lights were on 70-74 were h3 55w too.
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GeorgeRud |
Jan 7 2018, 02:53 PM
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#6
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Advanced Member Group: Members Posts: 3,725 Joined: 27-July 05 From: Chicagoland Member No.: 4,482 Region Association: Upper MidWest |
I wonder if there’s a LED replacement (with good reviews) for the H3 bulb? That would certainly cut down on the draw, but the ones that I find all seem to have poor reviews. Any personal experiences?
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hockeymutt |
Jan 7 2018, 03:31 PM
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#7
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Member Group: Members Posts: 84 Joined: 4-August 08 From: NJ Member No.: 9,388 Region Association: None |
I wonder if there’s a LED replacement (with good reviews) for the H3 bulb? That would certainly cut down on the draw, but the ones that I find all seem to have poor reviews. Any personal experiences? Have a pair of my daily driver not worth it, leds need a projector to throw the light out. 5 feet in front of my car they're super bright anything further it's hard to see |
windforfun |
Jan 7 2018, 07:01 PM
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#8
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Senior Member Group: Members Posts: 1,766 Joined: 17-December 07 From: Blackhawk, CA Member No.: 8,476 Region Association: None |
1 watt = 1 volt amp. Your current will therefore increase by 57 %. The fuse will probably blow before the wiring is damaged. The fuses are supposed to protect the wiring & not the loads. Don't use a larger fuse until you run a heavier gauge wire. This assumes that the fog lights are on their own circuit with its own fuse.
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somd914 |
Jan 7 2018, 07:04 PM
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#9
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Member Group: Members Posts: 1,171 Joined: 21-February 11 From: Southern Maryland Member No.: 12,741 Region Association: MidAtlantic Region |
Use a relay, the stock wiring can activate the coil. Run new wire just for the power. (IMG:style_emoticons/default/agree.gif) Good practice in general, especially with the old wiring and switches whose contacts have corroded and pitted. |
windforfun |
Jan 7 2018, 07:31 PM
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#10
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Senior Member Group: Members Posts: 1,766 Joined: 17-December 07 From: Blackhawk, CA Member No.: 8,476 Region Association: None |
A relay isn't necessary. Either way you have to run additional wiring.
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euro911 |
Jan 7 2018, 07:53 PM
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#11
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Retired & living the dream. God help me if I wake up! Group: Members Posts: 8,845 Joined: 2-December 06 From: So.Cal. & No.AZ (USA) Member No.: 7,300 Region Association: Southern California |
Wattage, divided by voltage = amps
35 watts / 13.8 volts = 2.5 amps (each bulb) 55 watts / 13.8 volts = approx 4 amps (each bulb) |
windforfun |
Jan 7 2018, 08:10 PM
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#12
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Senior Member Group: Members Posts: 1,766 Joined: 17-December 07 From: Blackhawk, CA Member No.: 8,476 Region Association: None |
So what's the current (ampere) rating of the fuse that supports this circuit?
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bbrock |
Jan 7 2018, 08:27 PM
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#13
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914 Guru Group: Members Posts: 5,269 Joined: 17-February 17 From: Montana Member No.: 20,845 Region Association: Rocky Mountains |
The wire in the fog light circuit is roughly 18 awg which is generally rated for 10 amp circuits. So, if the wires and terminal connectors are in good shape and clean, it seems like you'd be under the limit.
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mgphoto |
Jan 13 2018, 07:38 PM
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#14
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"If there is a mistake it will find me" Group: Members Posts: 1,330 Joined: 1-April 09 From: Los Angeles, CA Member No.: 10,225 Region Association: Southern California |
I've been running the 911 H3 adapted to my 914 housings. Never blown a fuse in 25 years.
Also been running 55/100 H4's for the headlights. But I do try to use the lighting wisely. |
VaccaRabite |
Jan 16 2018, 09:52 AM
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#15
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En Garde! Group: Admin Posts: 13,407 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region |
I've also run the H4 55 watt bulbs for quite some time without a problem.
Zach |
Mikey914 |
Jan 16 2018, 11:09 AM
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#16
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The rubber man Group: Members Posts: 12,625 Joined: 27-December 04 From: Hillsboro, OR Member No.: 3,348 Region Association: None |
Given that LEDs can have a much higher output, with an actual decrease in wattage, they seem to be a very viable candidate for "upgrade". You can do anything, at least for awhile. I used to drive to Wenatchee from Portland in the 80s and there were many spots in central WA where the oncoming trucks wouldn't switch to low beams. I put a set of aircraft landing lights in the fog lights after a few trips where I couldn't see jack when these bozos left their hi beams on. A flash of my hi's nothing one more time, and if not I'd light em up. Amazing how they could find the low beams quite easily when I kicked up the light for them. I did however wind up replacing some wires pretty quickly. Went to a relay system and ran another wire direct.
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euro911 |
Jan 16 2018, 02:13 PM
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#17
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Retired & living the dream. God help me if I wake up! Group: Members Posts: 8,845 Joined: 2-December 06 From: So.Cal. & No.AZ (USA) Member No.: 7,300 Region Association: Southern California |
lol
Back in the 80s, I installed an aircraft landing light on the rear of my '68 Baja Bug right below the rear window. At about 3am one morning as I returning home from a girlfriend's place out in Riverside, I was doing about 75 in the fast lane on the 91 freeway (4-lanes) and some jackwad came up fast behind me flashing his high beams. There were no other cars anywhere near us, so the ass could have easily gone around me. After he flashed me for about the 4th or 5th time, I lit him up for a few seconds. All I saw after that was his two headlights sort of merge into one in the distance - he backed of real quick (IMG:style_emoticons/default/happy11.gif) ... |
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