Re: rechargeable batteries(123) for an m60 dropin
James-
the best rechargeable solution for a 2xCR123 size flashlight utilizing the MalkOff M60 drop-in is a pair of protected 3.7V RCR123s.
Both of the links you have there are 3.0V cells, the "900mAH" 3.0V cell is a voltage regulated 3.7V cell, and the other is a LIFeP04 cell, while they both have their purpose, they both suffer from having less watt-hours when compared to a regular 3.7V cell. The M60 drop-in is designed to handle up to 9V, so go ahead and take advantage of that and use the pair of 3.7V cells..
Here's some links to what in my humble opinion is your best rechargeable solution to a 2xRCR123 powered malkoff M60:
http://www.lighthound.com/index.asp?PageAction=VIEWPROD&ProdID=1155
http://www.lighthound.com/index.asp?PageAction=VIEWPROD&ProdID=2190
Keep in mind that every RCR123 size rechargeable cell, regardless of brand, is heavily overrated on label capacity. 3.7V RCR123s all have about 500-650 true mAH capacity, all 3.0V "voltage regulated" cells (like those tenergy 900mAH you linked to) will also be around 500-600mAH but with less voltage delivered, so more wasted power in the delivery, and all 3.0V LiFeP04 cells are going to be around 250-400mAH true capacity.
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RGB LED-
While the Malkoff will operate on a single li-ion cell, it is a buck style regulator and will not maintain full brightness through the run. It probably starts off really close to full brightness on a freshly charged cell, but will dim down through the run, providing extended efficient runtime. This is acceptable behavior for some, but others may prefer it to stay at full brightness all the time.
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Eric