Mounted (Green) Laser Pointers and the Cold

I own 4 medium priced $80-$120 green laser pointers. All use AAA batteries (my choice for ease of replacement), but all do poorly in the cold.

Any tricks to maintain their use as mounted pointers without swapping out the batteries every 30 minutes in the cold? Do the Lithium ion batteries do better in this respect? Any other thoughts? Get a better laser? I need one with a constant on (not toggle) switch. Are there models that excel in this respect?

Thanks.

Marc Whitsett
Cincinnati, Ohio

Marc,

If you are leaving the lasers constantly on, it will juice out the batteries pretty quick. 30min constant on time is pretty good for a 5mW unit. Lithium Ion will probably not be much better in cold weather. You might try a nickel metal hydride battery though. I'm not too familiar with this chemistry but i believe it has better cold temperature performance than LiIon. The energy density is not as good but they may last longer in the cold. If you really want outstanding cold temperature performance, go with nickel hydrogen. Performance in this chemistry actually improves as temperature drops. Unfortunately, the smallest single cell I am aware of is about 2.5 amp hours in capacity and looks nothing like a AAA cell, and, oh yeah because of the platinum catalyst and space rating, will cost about $10,000. It will last over 20 years though!

Why not use an external battery to power the laser? You could assemble a quick and dirty regulator to work off a 6 or 12 volt battery and one of these should run the laser for next to eternity. Or add an external battery pack and use D cells. These will outlast AAAs.

dan