From what I read the UF-H3 will run over 400 hours on low and over 3 hours on high. Just have a couple spare 18650 cells and you can have well over a month straight of light. Use it only 12 hrs a day and it goes to a couple months. I can't imagine wanting more than that. To those that have the UF-H3 is that 400 hour claim true??
Edit: Just searched and found Don's review on it and he tested it to be 168 hours on a 2500mA cell. That's still a week of straight running! Two weeks at 12hrs a day and with a couple spares it's a month and a half. Damn! I think I'm going to get one for sure now.
I already have a UF-H2 and for an AA light I'd have to recommend it. Mr Admin did a review and a full rundown test and here is what he found...
With an Eneloop, the UF-H2 ran for somewhere between 80 and 84 hours nonstop. That's more than 3½ days on an Eneloop! The runtime results were even more impressive with a common Rayovac alkaline AA battery-- it ran for more than 116 hours, almost 5 days. During the entire duration of the runtime test output was impressively flat; even with the alkaline I noticed very little battery fade toward the end of the test. It finally just shut off. I should mention that the output on this low level is actually very usable indoors at night. If I had to pick a single light to use while trapped in a mine with just one battery, I would pick the Ultrafire UF-H2 hands down.
