Hot Rod Forum banner

Upgrading to Halogen Headlamps Question

3K views 21 replies 10 participants last post by  ogre 
#1 ·
Looking at an H4 upgrade kit for my '59 pickup. I already have a painless harness and fusebox - do I need to add a relay to the circuit between the headlamp and dimmer switch; or should I add 2 relays after the dimmer switch?
 
#2 ·
I have a Painless harness and just upgraded to H-4. I added 2 relays and a 25 amp fuse after the dimmer switch. I gained a full volt at the headlights. I use the headlight wires from the dimmer switch to trigger the relays. worked great. There is very little current at the dimmer now. Before it would get to 175 deg F in about 2 minutes.Eventually it melted the connector and the switch.

I used a Radio Shack project box for the relays and fuse holder. 12 ga wire for the power and grounds.

The focus of the lights is still terrible. At best I have to compromise on where the high beam is. Between the normal high and low is the best I can get with my current lenses. Low beam just lights up the ground directly in front of the car.....useless. :(

There has the to be a better bulb than the H4.
 
#5 ·
vicrod said:
Also, the Hella headlamp #70-477 provides very good optics that takes full advantage of the H4 bulb.
vicrod
I also have the same problem with my lenses that bentwings mentioned. They are plenty bright but focus terrible. I have considered the Hella lenses, but at $75 a pop I can put up with mine for no more than I drive it.

Vince
 
#6 ·
I'm about to try this on my lemans but i'm going a lil bit further with the H4 conversion but then adding HID kit to really get the most out of them. I added the HID kit to my daily driver and I can tell you I will not be driving any more cars in my lifetime without the kit! And at only 40 bux including shipping on ebay with lifetime warranty, how can you not? This kit works on ANY bulb even the new cars. I live in Colorado where there are elk,deer,coyotes,fox and even bears that get hit on the road and highways, so I need as much light as I can possible get and for my daily driver, it was litteraly a night and day difference!
 
#7 ·
I just switched to the 9003 halogen sealed bulbs and they are plenty bright. Just last night, I noticed that my light switch feels warm, not hot to touch, after driving with the low beams on. I'm wondering if I should install relays? I was looking at the diagram for 1 relay that Vic posted. What the heck is a "coil" on the diagram? Are they talking ground?
 
#9 ·
302 Z28 said:
The "coil" is the coil of the relay. This is what creates the electromagnetic force that operates the relay.

Vince
Thanks Vince for explanation. I'm going to throw this out for what it's worth. I have several friends who have changed to the H4 lighting. They swear by IPF lights and lens for projection and even protection against rocks etc.. Here's the website if interested.

http://www.ipf.co.jp/English/index.html
 
#10 · (Edited)
I was looking at these bases "euro" Crystal Clear Diamond headlamp bases at GM Pauls, $40 a pair - the bullet in the middle looks pretty retro



Their H4 bulbs are $13 a pair, but I was thinking about better bulbs anyhoo

Great posts by vicrod and Irelands child - thanks! But in thinking about vicrod's single relay, the bulk of the load is coming off the headlamp switch feeding the relay at terminal 30, I would think you'd want to avoid that... am I missing something?
 
#14 ·
There has been alot of debate in here over whether or not to use relays for headlights. It's not that big of deal to install them. I'm going to install them but I think I'd rather go with the dual relay vs. the single relay method. (one relay for low beam and one for high) just to be safe...
 
#16 · (Edited)
i'm not sure what the purpose of a single relay would accomplish (as posted by vicrod)
all the load is still going thru the headlight switch, the main panel and wiring.

double relays, as posted in 302 Z28's 2nd diagram (the understandable one) has only the control load going thru the switch, dimmer and fuse panel.
the headlight load is carried thru the #10 wire only that is connected to the battery.

i think #10 is a bit overkill and could easily be a #12.
the single relay setup would still overheat the headlite switch

using 2 relays the idea is to mount them on the radiator support or inner fender
you could mount them under dash but it would add more wire and potential voltage drop to the circuit.
with 302 Z28's diagram you could change out the headlight fuse to a 5 amp fuse

ogre
 
#17 ·
That was what I was thinking too. I just added relays to my car with H-4 almost exactly like "the understandable one". I used 12 ga wire for the power and the ground. I did not see any rise in wire temp after 2 min testing.

The dimmer switch terminal temp went from 175 deg F in 2 min to ambient. The headlight switch is up under the dash so I couldn't get a good shot at it but it is markedly cooler to the touch. It is still warm due to the resistor for the inst dimmer but not "ouch" hot like it was before the change.

The lights are much brighter now but I still can't get a good focus for both. I think the only solution is to use an OEM reflector of some sort. It will be a major problem to mount it in the original repop buckets. There just is not any suitable mounts to start with.

I'm open to solutions.
 
#19 ·
I think the 2 relay system is better (safer) in that if one drives the high beam and the other drives the low beam you will still have one beam set operational if the other fails. ie relay fails. This assuming the system is parallel wired.

In the real world adding the relay system means ripping up a lot of wires, at least in my case. All of the wires from the firewall forward are incased, hidden and heat shielded so the entire pile of wires had to be opened up. It would have made no difference one relay or two. The cost of the relays is minimal. I was able to use the trigger wires from the dimmer but I also color matched the new wires to the headlights and used black for grounds as I have done throughout the car. Black is always a ground on this car. In the end material cost was also minimal as I had everything to do the job. My labor to do the job was what was difficult.
 
#21 ·
headlight upgrade

I need to upgrade the headlights on my antique 22 Ford speedster. the original 3 brush generator won't keep up with the ingition and lights, ( no magneto on this engine), I have modified a 60's ford pickup generator to use the the T gear drive. Has anyone fit the GMC paul's headlite bases to fit in a T electric or 14 style carbide lantern headlights ? I wonder if there is enough space behind the reflector.
 
#22 ·
vicrod said:
See attached schematic using (2) relays.
This arrangement has all the load of the headlights passing through the relays and only relay coil and dash light loads passing through the headlight switch and the dimmer switch.

vicrod
my only issue with that dwg is that most of the time your headlite switch is wired into a harness and into a fuse panel. the use of relays and trying to get the most power to your lights would need a wire and fuse off the battery to the relays, independent of the smaller wire and smaller fuse to the switch.

bentwings: good feedback on actual temp readings, before and after, to drive home the point
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top