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914World.com _ 914World Garage _ 55w driving lights on a 35w circuit

Posted by: 72 IXXIV Jan 7 2018, 11:23 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?

Posted by: Elliot Cannon Jan 7 2018, 11:29 AM

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.

Posted by: mihai914 Jan 7 2018, 11:41 AM

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?

Posted by: Mueller Jan 7 2018, 12:12 PM

Use a relay, the stock wiring can activate the coil.

Run new wire just for the power.

Posted by: 914Sixer Jan 7 2018, 12:17 PM

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.

Posted by: GeorgeRud Jan 7 2018, 02:53 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?

Posted by: hockeymutt Jan 7 2018, 03:31 PM

QUOTE(GeorgeRud @ Jan 7 2018, 12:53 PM)

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

Posted by: windforfun Jan 7 2018, 07:01 PM

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.

Posted by: somd914 Jan 7 2018, 07:04 PM

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.

Good practice in general, especially with the old wiring and switches whose contacts have corroded and pitted.

Posted by: windforfun Jan 7 2018, 07:31 PM

A relay isn't necessary. Either way you have to run additional wiring.

Posted by: euro911 Jan 7 2018, 07:53 PM

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)

Posted by: windforfun Jan 7 2018, 08:10 PM

So what's the current (ampere) rating of the fuse that supports this circuit?

Posted by: bbrock Jan 7 2018, 08:27 PM

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.

Posted by: mgphoto Jan 13 2018, 07:38 PM

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.

Posted by: Vacca Rabite Jan 16 2018, 09:52 AM

I've also run the H4 55 watt bulbs for quite some time without a problem.

Zach

Posted by: Mikey914 Jan 16 2018, 11:09 AM

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.

Posted by: euro911 Jan 16 2018, 02:13 PM

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 ...