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> 55w driving lights on a 35w circuit
72 IXXIV
post Jan 7 2018, 11:23 AM
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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
post Jan 7 2018, 11:29 AM
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QUOTE(72 IXXIV @ Jan 7 2018, 09:23 AM) *

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)
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mihai914
post Jan 7 2018, 11:41 AM
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That's 157% over of the original load, wouldn't quite say it's within the margin of error or the overhead engineers calculate. If you add to the fact that it's old wiring exposed to elements it's worse.

Heat buildup in the housings will be an issue also and will probably affect the wiring first.

Have you considered LEDs?
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Mueller
post Jan 7 2018, 12:12 PM
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Use a relay, the stock wiring can activate the coil.

Run new wire just for the power.
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914Sixer
post Jan 7 2018, 12:17 PM
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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
post Jan 7 2018, 02:53 PM
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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
post Jan 7 2018, 03:31 PM
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QUOTE(GeorgeRud @ Jan 7 2018, 12:53 PM) *

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
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windforfun
post Jan 7 2018, 07:01 PM
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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
post Jan 7 2018, 07:04 PM
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QUOTE(Mueller @ Jan 7 2018, 01:12 PM) *

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.
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windforfun
post Jan 7 2018, 07:31 PM
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A relay isn't necessary. Either way you have to run additional wiring.
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euro911
post Jan 7 2018, 07:53 PM
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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)
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windforfun
post Jan 7 2018, 08:10 PM
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So what's the current (ampere) rating of the fuse that supports this circuit?
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bbrock
post Jan 7 2018, 08:27 PM
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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
post Jan 13 2018, 07:38 PM
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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.
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VaccaRabite
post Jan 16 2018, 09:52 AM
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I've also run the H4 55 watt bulbs for quite some time without a problem.

Zach
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Mikey914
post Jan 16 2018, 11:09 AM
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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
post Jan 16 2018, 02:13 PM
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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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