Ken, now that you've had this light for a couple months, presumably using it in your cold barn, I'm curious if you ever tried lithium AA's in your Survivor LED?

I read a post over on CPF a little while ago that seems to imply that using lithiums are OK, although inefficient. I can't find the post right now, but someone hooked up the Survivor electronics and LED to a test bench and observed what happened as he slowly ramped up the input voltage. Over 4.8V, apparently the Survivor's converter "dumps" the extra current so the LED doesn't get any more power as the input voltage goes up, even up to 8.0V. I assume the extra current is simply lost as heat, which is normally not good, but if you're working in the cold, that may be OK for the LED and the electronics. Besides, as the temperature drops, so will the voltage of the batteries, even lithiums, so excess heat may be even a lesser problem than I'm laying out here.

In its intended environment--fighting fires--I can see how a build up of heat would make Streamlight say that lithiums shouldn't be used, but in your case, this post seems to suggest that you'd be OK. Well, another reason for Streamlight to officially discourage lithiums is because the light is not safety rated with lithiums, so they don't want fire fighters going into harm's way with potentially dangerous lights.

Anyway, take it for what it's worth.