HID doesn't light up. Lamp or ballast?

[jirik_cz]

My friend brought me his Trailtech 13W HID bike light. One day he just switched it on and it didn't light up.

Is there any way how can I identify if it is a bad lamp or ballast? I've checked the battery and it works fine. Thanks!

 

[BVH]

Have you tested the battery under load using a 12 Volt, 3 Amp load? Do you have a 50+ watt, 12 Volt light bulb you can light up directly from the battery using jumper wires? Maybe a car headlight bulb. Chances are, your normal 1 Amp system will require about 2.5 to 3 Amps to start the bulb. And although your battery may read 12+ Volts with no load, (your 11.1 V battery will probably read about 12.5 to 12.8 when fully charged) it may not supply enough Voltage and current under load.

In my opinion, the order of probable failure is:

battery
faulty or dirty wiring/connectors
ballast
bulb

I know of no way of testing the ballast and bulb other than to swap with other known good ones.

 

[jirik_cz]

I've tried to connect the original battery (11,1V) to my triple Cree MC-E light (about 30W) and it worked just fine.

But then I've tried to connect my 14,8V battery directly to the HID ballast and the lamp fired up! After that I've tried the original battery again and it works now too

 

[Patriot]

Weird. Maybe during the swapping process a contact or connection issue was disturbed and is now making better contact.