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[All information is Copyright 2000-2003 Robert Laird]

This graph was generated while an Extreme-Exposure HID light was "burned" in a tub of water, powered by a cannister light battery (i.e., 2  12-volt  7-ah batteries in parallel). For this test, I selected my "worst" battery pack, Interstate.

A point was recorded every minute. The beginning voltage was 13.1 volts, and the recording started right when the switch was turned on. The light took about 2 minutes to get to "full burn" and then took on a linear usage on volts. Right around 4 hours, the voltage started dropping precipitously, and the light actually went out at 4 hrs, 28 minutes, where the voltage was at 9.62 volts. The light flashed (about 5-10 flashes per second) for about 2 minutes before going out, so there was some warning. What's really interesting is that, with the switch still ON, the light acted like the switch was OFF, and the voltage quickly crept back up to around 11 volts. After a few minutes, I was able to turn the switch OFF, then back on, and the light came back on, but I didn't want to add additional stress to the battery, so I didn't test how long it would stay on after that.