I have actually gotten to use my D26 1600 now and I am also seeing a serious problem with self-discharge even when the light is off. At first, I thought maybe I had put in a battery that I had forgotten to charge. But, now I've tried it over 4 or 5 days of diving and it seems like it is burning through the battery at the same rate (or nearly so), whether the light is on or off. I put a freshly charged battery in at the beginning of the day on Saturday, did 2 not-long dives, used the light for something like 25 minutes on the 2nd dive and not at all on the 1st. The red LED was flashing at me by the end of the 2nd dive.
So far, it's somewhat anecdotal evidence. But, now that I'm pretty convinced I'm going to do some actual testing.
I also sent an email to Xtar to inquire if they are aware of this issue. Hopefully, they will acknowledge and provide a fix (i.e. update the design and send me a new light). The brightness of it is truly awesome. But, it seems to be running down so fast, I am just about ready to call it unusable.
So far, it's somewhat anecdotal evidence. But, now that I'm pretty convinced I'm going to do some actual testing.
I also sent an email to Xtar to inquire if they are aware of this issue. Hopefully, they will acknowledge and provide a fix (i.e. update the design and send me a new light). The brightness of it is truly awesome. But, it seems to be running down so fast, I am just about ready to call it unusable.