Re: NVG BATTERIES - ever had a problem?
Never had a snag with the mil lithiums and useage was over regularly over 20 hours - this was early 90's. The batts are now, though, changed after each use.
The one snag with the AA lithium is I once used one in a torch and placed the battery the wrong way round to prevent inadvertant illumination, and was mildly surprised to feel the aluminium torch body intensely hot after about 15 minutes. The battery had expanded and was extremely hot to touch and was short finals to going bang, I reckon. A common 'feature' of lithium batts, apparently.