Originally Posted by MileHighMark

Yes, I ran the light on low. No, I never confirmed the 8-hour (low-beam) run time. Why? Because 90% of the time, I ran the light on the high setting. And on the high setting, the charge/run-time was as-claimed. Why did I run the light primarily on the high setting? Because I ride on pitch-black back roads (say that 5x fast) where the speed limit ranges from 40-50mph (and drivers typically exceed the 50mph limit). This is the first light that I haven't out-run on (paved-road) descents.

The photo below (which is included in the review) illustrates how the high and low settings compare: