h4 headlights and relay

[jaydub01]

i am converting to an apc h4 headlight system, and i have heard about the relay to get more power, and a brighter, stronger light. Ive been looking at some wiring diagrams, and the max capacity is a 50 watt headlight, but the conversion bulbs are 55, and i was wondering if a relay would help power these. Also do you run dual relays from each headlight, or just one that splits off to both???thanks for any of the help

 

[bert]

A 55 watt headlamp should draw less than 5 amps. A quality relay rated at 20 or 30 amps should run both headlamps just fine. Be sure to include a fuse.

 

[Skuzzlebutt]

I think you misread something. It is prolly a 50AMP relay, which should good for upto 600 watts. The more common 30 amp relays are still plenty strong for headlight use.

Even stock headlights are 55w low beams.

You do want two relays for a conversion. Not one for each side but one for low beams & one for high.

 

[73stallion]

i didn't use a relay on my H4's and they are much brighter than stock.i think my lights are 65/80 watt instead of the stock 50/55 watt. i opted for the blue bulbs and what a difference.

 

[mitzel]

my non-expert opinions:
- if you're sticking with the standard 55/65W halogen upgrades you should be able to get
away with the stock wiring like 73stallion mentioned. make sure your wiring is in good
shape and headlight switch and dimmer switch connectors are corrosion free, otherwise
you may get annoying and dangerous headlight flashing. but you can get even better
performance going to the relay-ed system and also easily design the system for even
higher wattage bulbs.
- I agree with bert and Skuzzlebutt, you're probably misreading the limit on relay capacity.
standard bosch relays are typically rated at 20-40amps, more than enough for headlights.
I also agree with Skuzzlebutt that you need two relays, one for low beam and one for
high beam. look for the relays with two #87 terminals (that's the high power output to
drive the lights). that allows connecting each light directly to a relay terminal rather than
having to add a split somewhere.
- use 14 gauge or larger stranded wire for the high power runs.
- I disagree with others on the stock bulbs wattage. I think the factory original sealed
beam incandescent bulbs were 45W low beam. the 55W replacement halogens are
a step up in both technology and wattage leading to significant increase in light output.
and with the relays and improved wiring checkout the 55/100W bulbs, they rock!
- regarding recommendations for blue bulbs: a xenon bulb may have a slightly more blue
tint and are very good bulbs. the bulbs with a blue coating to change tint are a bad idea;
they're largely a marketing gimick to mimic xenon/HID coloring and result in lower light
output and increased glare compared to a clear bulb of the same wattage.

 

[kwspony]

my local napa had the relays with 2 #87 posts. $14 or so. If you have a problem finding them I have the reciept here somewhere, I can get you a part number.

 

[TOFIC]

my local napa had the relays with 2 #87 posts. $14 or so. If you have a problem finding them I have the reciept here somewhere, I can get you a part number.

GAWD send me the part number, I been looking for months and none of the "parts guys" have a clue what I am talking about.

TOFIC

 

[mitzel]

walker949
> I been looking for months and none of the "parts guys" have a clue what I am talking
> about.

if you give up on local suppliers del city is a good online source <http://www.delcity.net>.
I think the part#73996 is a dual #87 relay for $5.62 each. check out the 'relays and power
distribution' link then 'relays' link for a bunch more relays.

 

[vbro]

relay schematics

HERE is a post that has the wiring diagram.
Hey KWSPony do you have that p#?

 

[kwspony]

the part number on the box is AR274 for the relay.

 

[flint_knapper]

autozone has the dual "87" contact relays for $4 bucks and some change.
the part # is DF005 at the local place
they are near the off road lights. look for "baja tough"
that is also on the pack they come in.

 

[broncoman1972]

My .02 on the subject.. It was mentioned earlier to make sure to fuse the circuit. I disagree slightly. I would use 30 amp circuit breakers (one for high and one for low.) This way if there is a problem the lights will at least come on at times. Better than nothing....

I run the Hella h-4's on a relayed circuit with Hella's stock bulbs. I haven't seen the need yet to go brighter.

 

[jaydub01]

kwspony, i used your diagram, and when it was all hooked up, only one headlight would go on highbeam at a time, while the other was on low, then they'd switch when i would hit the selector. i re checked all my work and its all right, has anyone else had this problem, and how do you fix it????

 

[kwspony]

the stock low beam wire ,red with black stripe, goes to post 86 on one relay, then a wire from post 87 of that relay goes to the headlight. 2 wires if you have dual 87 posts. 1 for each low beam at the bulb. The stock hi beam wire, green with black stripe is wired the same way on the other relay. Don't forget to ground the 85 posts on the relays. the 30 posts come from the battery. From what you are saying it sounds like it is wired wrong somewhere.

 

[Skuzzlebutt]

There are two types of relays with two output posts on them. One has them both on or both off. The other has them so one or the other is on but never both.
But I guess that would cause something different so nevermind.

It sounds like you have each relay wired to one hi & the opposite lo beam instead of the way they should be.

 

[mitzel]

each light has three terminals: ground, low beam power, and
high beam power. right? sounds like you have the low beam
power and high beam power swapped on one bulb. I believe
that's what Skuzzlebutt was suggesting too?

when your dimmer switch is in the 'low beam' position check the
connectors to the light that's on high beam. my guess is that
the hot power wire coming from the low beam relay is connected
to the high beam connector on the light. if so then just swap the
two power wires on that light and you'll be golden.