I have a CR123-size Zebralight flashlight, and the problem I have is that it goes dead fast. The highest brightness level becomes unusable only partway into the battery's true life. The rest of the levels work fine. My Fenix light would keep working for a long time on high, but the 'high' would just be less high as the battery wore out. With this light, the flashlight shuts off suddenly, and since the interface encourages you to start it up on high mode, this becomes frustrating behavior quickly, because you turn the thing on and it works for a few seconds and then just turns off completely. I'm wondering if this is a known issue with these lights, and if there's anything I can do about it. This leads to me throwing away a lot of partially-discharged batteries and cussing.