H4 headlights

Greetings

Looking for help in wiring for H4 headlamps.

Plan on using Bob Drake H4 reflector conversion kit.

I don't know what the current requirements are for the H4 bulbs versus more traditional bulbs. I have call in for harness manufacturer's tech help line for info.

I have installed two relays for powering the low and high beam circuits but can't determine if the wire size in the new harness are adequate for the H4 bulbs.

Also I think, NAPA has high temp H4 sockets.

Thank you for any input.
Jack

 

take watts (55/45 usually, but up to 165) and divide by volts (13 in a 12v system) and you get amps.

Run the amps number (4.25, typically) and the feet the wire has to run into Google, and you'll find good advice on wire gauge.

If originality is not important, run a relay and power the lights from the alternator/generator, and the switch on the dash can turn the relay on and off.
I did this on my 63 Volvo with 100/130 bulbs, and no car with just two headlights put out more light.
OTOH because the styling of the Volvo 544 places the headlamps so low you had dark pools where the headlights couldn't reach into the dips in the asphalt, on anything but completely flat road. That and street signs blinded you in built up area. It's all a compromise.

 

need atleast 10 gauge for the newer style bulbs, heat from lamps will destroy old wires.

 

The simple, correct answer! Just run a pair of relays and life will be sooooo much easier... And brighter! As a side note, I've run H4s in all of my cars for the last 25 years now. If you run without relays, the first thing that you will find a problem is headlight switches in an early car. They just aren't made to carry that much current load on a constant basis. The relay sets it up so the switch is in actuallity just turning on the low load of the relay. Sound complicated, but it's really not.

 

Do what Need louvers ? said and get a pair of relays. From experience the higher output H-4 bulbs draw more amps then the headlight switch and dimmer switch want to handle.

You have to think past the quad light setup on this but it is a good diagram for hooking up the relays.