Hello. I've went through two sets of 4500K HID lights (both Hi/Lo beam), after replacing the stock lights they work pretty well... but burns out in about 1-2months... whats going on??? Is it the quality of the HID lights I've bought?

 

sounds like you have high wattage bulb and not HID bulbs that uses a ballasts but I wouldn't recommend putting a HID kit into stock housing as it's glare is blinding to oncoming traffic if you want HIDs consider doing a retrofit.

 

could be anything. My suspect is that the O ring that seals the headlight might be missing. This would allow condensation to build on the inside of the housing and ontop of the fragile HID bulb.

 

could be a cheap brand of bulb too. Silvania's work well but they go out after a year or so. Which if you think about how hot that little wound wire is thats not bad.

 

what would be a quality/dependable brand for HID bulbs?

 

They aren't HID bulbs. HID stands for High Intensity Discharge, something that uses ballasts and as already described. It uses electrical energy to jump a gap like a spark plug, but uses the voltage to produce a light. What your describing sounds like the blue or yellow or purple headlights you can buy on ebay for like 30 bucks for two. Those lights are more for show. If it says it uses a higher voltage than 55watts stay away. The heat generation casues the small filament to melt or heat up and when it cools it cracks and then that causes the filament to break and then goes the light.

If you want that effect get some Silvania silverstars or Silvania ultra's. They are great lights and i love them. Silverstars are about 40 or 50 bucks a pair and are more than enough to produce more light than a regular halogen. They aren't HID's though, just higher powered halogen's. There's also Xenon gas bulbs but i've never used those. Sounds like another knock off of an HID system.

Check out www.howstuffworks.com and look up HID if your really curious what the difference is.