I normally use NIMH batteries in mine. I believe Malkoff even recommended them for his higher output Maglite drop-in, that I don't see on his site at the moment. I know everyone has different needs. If there was a way to do a high low ring I would really like that too. I have just always wanted a low mode option on Maglite, I have even emailed them about it. The eco made on the newer ones increase runtime, but it is still too high for my liking. I guess that is why I don't use them as much as my other lights. I am not sure how long a moonlight mode would last on 3 D cells, but I would imagine, quite a long time.