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Old 08-30-05, 10:08 PM
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Dougmt
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Originally Posted by Sloth
BTW, I just checked. A Cygolite HID bulb assembly will start and run just fine using an off the shelf 12V NiMH battery pack. The startup behaviour is identical to that using the Cygolite battery (i.e., an initial warmup period, etc.)

I would guess that they have both a regulator and a ballast in there. Probably a soft start mechanism as well, if one is needed.

Interesting.

The ballast is built into the light assembly and I think the newer HID MR11 style bulbs have the ballast built into the bulb itself.... the regulator is for using LiOn batts that put out WAY more than 13volts for the first few minutes or so... that much voltage will kill the HID bulb.... NiMh and NiCad don't have that problem.
batteryspace.com has an EXCELLENT primer on the HID bulbs...
Doug
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