Was thinking about changing to something like a H4 bulb this year, anybody have problems with fiberglass meltdown around headlight bucket ? thanks
Original Post
Replies sorted oldest to newest
No you're good but do change out the headlight wiring to the next heavier gauge and use a relay.
Follow the doctor's orders.
I put in H4's about a year ago and then upgraded to heavier wire (and relays) about six months after that.
The rewire made as much difference as the H4's.
Maybe do the rewire first - you'll need it to take full advantage of the H4's, and you may find it's enough of an improvement that you don't need to bother with the new lamps.
is one 5 pin bosch relay enough for both headlights or one relay each side thanks, Darrell
Use two relays.
Widebody, I think Mr. Ed meant use two relays - one for the low beams and one for the high beams. At least, I hope that's what he meant.
Most high beam bulbs are 60 watts, so 120 watts for the pair. At 12 volts, 120 watts will draw about 10 amps, and most 'Bosch' type relays, even the cheesiest ones, are rated at a minimum of 30 amps (some are 40). So, a 30-amp relay is operating at about one-third its rating with 60-watt bulbs.
Premium 100-watt bulbs will increase the current draw to 17 amps, so a single 30-amp relay would still be OK, but a 40-amp relay would have a better safety margin in that case.
And don't, by the way, hook things up so that both high and low beams can be on at the same time. Headlight bulbs weren't designed to work that way.
Well, the number of “pins” on the relay doesn’t tell you much more than it is a “single pole double throw” style (which would be good for both lo and hi beams). You need more info than that.
The real answer is to look at the current-carrying specs for the relay you choose to use. It should be able to reliably handle at least 30 amps at 12 volts (switched) for use with a pair of H4 headlights. Less than that and either the relay will heat up or the lights will be dimmed due to unwanted resistance in the circuit.
Here’s a good, inexpensive one to use, or one similar, at a 40 amp rating:
https://www.superbrightleds.co...mzpTtosaAlz0EALw_wcB
Sorry for the repetitiveness with Mitch. Posts passing in the night.......
Why not just change out to superbright led's ? Your current wiring will then be "oversize" !.................Bruce
Bruce any idea where I can get the led's ? I'd go with that over putting in the relays, Darrell
superbrightleds.com has H-4 LED bulbs..............Bruce