Pitfalls for HID conversions (H4 and the like)

[jankj]

I'm intrigued by the possibility of getting a high output HID for a reasonable price simply by adding HID bulb and ballast to a conventional halogen automotive light (or a handheld searchlight with an automotive bulb). It is very tempting to assume it would be as simple as replacing say, the stock H1 halogen bulb with a HID H1 kit. Specifically, I'm looking for either H1 or H4 HID bulb that isn't the cold, blue/white color, but more like 4300 K. And - most likely I'll try to scoop out something from Ebay.

But what traps are there to look out for? Am I just overly pessimistic, or are there some traps here, such as different flavors of H1 / H4 bulbs, different placement of the bright stuff (not in focus), quality issues and so forth. I assume there are some obscure codes that describes such things - what are they?

Also - what is the typical operating voltage range of the ballast? I've heard 12-16 volts, but how far down can the voltage drop before there is a problem powering the light?

What is the real world power consumption of say, a 35w HID? I know there will be some high amperage startup draws, but given there must be some losses in the ballast how much power must I supply after the warmup time? 40-50 watt?

 

[alpg88]

i converted 2 lights to hid, using auto h3 kit, but you got to make sure your light is 12v, not 6v, in both my lights i had 100w h3, so swap was pretty simple, it gave me longer runtime like 2x as long or even more. brightness wise i didn't win much, 35w hid is about as bright as 100w halogen. beam quality is just as shitty as it was with halogen

 

[BVH]

Modding the handheld spotlights is fairly straight forward. Many of the ballasts in Auto kits can go as low as about 9.6 Volts and as high as 15-18 Volts. Ballast efficiency is not good on most of them. If the seller is giving you true "to the bulb" Wattage, then add about 27% to get overall power consumption. But even with that, you will generally get some good run times because it's less than half of what the 100 watt Incan consumed. Shimming the bulb can be a bit tricky depending on which direction the bulb needs to be shimmed - if at all. If you're within a 32nd of an inch of where the incan filament was, you're going to get good focus. Just measure with a small scale before and after. Sometimes, depending on bulb style, modifying or making a new clip that holds the bulb in can be a challenge. On the Thors, there was usually enough room to house the ballast behind the reflector without any modding. Especially, if you go for the slim ballasts. Other than that, not much to it. Going from a 100 Watt incan to a 35 (at the bulb) HID won't yield too much increase in Lumens but you should get better throw out of it. If you get a true 55 watt at the bulb kit, you might see a doubling of the Lumens.

 

[M@elstrom]

Biggest pitfall I've seen is where the person converting the spotlight doesn't bother to focus the new "HID" bulb assembly giving them a nasty pie-in-the-beam artifact (see below) :thumbsup:

Bulb placement in the reflector is 100% relevant!

 

[Norm]

Have a look at some of the conversion related posts on CPF you could start with the one in M@elstrom's sig line.
Here's mine Aldi HID build
Mine uses a slim ballast which seems to be more modern in design an seems to have better efficiency than some of the larger ballasts. Start up current is about 5 Amp and run current about 3 Amps and is much brighter than it was standard, run time has gone from about 20 minutes to an hour.
Norm

I sure you find plenty of other similar builds also some much more complex build too.

 

[M@elstrom]

If you follow Norm's approach (and selected components) you'll be in the lucky minority who don't actually need to focus the HID bulb within their project :thumbsup: