Lithium Ion batteries in cold weather?
 

They have a rep for poor performance, no? I'm thinking of picking up the new model of the NightRider MiNewt, which comes with a lithium ion battery pack (right?) but I'm concerned about performance in cold weather as, after all, most of my night riding (commuting) is during the cold winter months here in NYC.

They'll probably do well enough unless you happen to move to Minnesota;) Keep your batteries (and light) inside during the day so that they are relatively warm when you head home. It takes a while for the battery to chill and the electrochemical reaction will generate some heat. If it's too cold, get a longer lead and put the light on your helmet (probably better anyway) and keep the battery next to your body...kinda the 'heater cat' approach;) 98F is plenty warm.

Lithium ion batteries will last longer in the cold than NiMH will though.

True. Nimh will quit working when it get below freezing.

Plus the LI weighs much less. But you pay a premium for these benefits.

BS. I use Nimh all the time below freezing. The only trouble i have EVER had was with my cell phone when it was -5 F, which happens to be 40 degrees below freezing.

Sounds like I shouldn't worry. Thanks BF!

NiMH, Li-ion and SLA all have about the same temperature threshold... about -4F...NiCd will continue to operate down to -40F. Don't try to charge any of the batteries when they are cold. Let them warm (or cool) to room temp before putting them on the charger.

I use a Li-Ion pack from Batteryspace.com for my lights. The pack was fine even at the lowest temperatures, -20C or so. I brought the pack inside only when it needed a charge, otherwise it stayed in the unheated garage.