Q:How to identify hid ballasts good or bad? 

A: a light one second luminous flux in accordance with international standards of 20%, 4 seconds to more than 80% brightness is qualified ballast, the HID ballast can reach 80% brightness in a second, two seconds to reach standard brightness. Truly a moment of light flicker-free dimming at night the whole car is very helpful. Two ways to start, the start of the ballast divided into two, first, cold start, when the lighting HID ballasts and bulbs in a cool state; two hot start is the ballasts and bulbs in the normal operating temperature when lit. This state, you do repeatedly continuous switching action, the good quality ballast lighting, and some HID ballast lighting is not normal bulbs there will be a bright one bright phenomenon, the need to cut off power to restart, after apparently poor quality.