I have a pair of Hella 7" round lights in big ol' plastic cases for roof-mount. I got them from my uncle, and they're not wired at all. They're H4's with lo/high beams...

 

2 Q's...1. anyone know the wiring for them? I've got three contacts, and I'm not sure which is high, low, or ground. I could just try 'em, but I'd like to make sure I get it right.

 

2. would it be ok to run both filaments at the same time? I've got combo driving/fog lights on the front that I run both on at the same time, but they're individual bulbs, these are 2 filaments in the same bulb....would the heat be too much?

1. not sure, but do you have a multimeter? one pin will be common to both (ground), the high beam filament will have a slightly lower resistance.

 

2. They last a little while like that, but not long. You can get H4s in really high wattage though (like 115/120 or something).

pick one to try for a ground. then start trying the other two, its very easy to figure out once you start playing with them.

you cant hurt them this way, so theres no real danger

 

 

maybe someone else will chime in that knows for sure, but i think the one by itself is the ground.

H4s are awesome,

run two individual circuits, and a relay for each.

One for low and one for high.

Get some 130w/90w bulbs and light up your entire zip code.

DO NOT run both together. (sorry if I sounded like a mother)

They blow within 5,4,3,2,.... you get the idea.

I have them in my headlights and in my drivers (highbeam only)

 

Cheers, Matt

Also.

If possible, make sure you use stabalizing bars at the top.

Vibration is what kills H4s, they get waaay hot and fragile, a tiny movement due to flex causes tremmers and blown bulbs.

 

Get a 6 inch worm drive stainless hose clamp and open it up as a strap.

Srew one end to the top of the light and tension them up against your bodywork.

Also.

If possible, make sure you use stabalizing bars at the top.

Vibration is what kills H4s, they get waaay hot and fragile, a tiny movement due to flex causes tremmers and blown bulbs.

 

Get a 6 inch worm drive stainless hose clamp and open it up as a strap.

Srew one end to the top of the light and tension them up against your bodywork.

 

hmmm...this is a good idea, unfortunately they're mounted on my roof rack, pretty solid mount, but nothing above to mount the top to. and they'll be pretty much off-road only lights, so there'll be lots of vibration to worry about. maybe lower wattage might make them last longer?? we'll see this weekend!

thats what is in my motorcycle. higher watts do seem to burn out very fast compared to stock ones. and my bike has very bad vibrations