us battery in cold weather

a friend of mine purchased the ultrastinger on my recommendation.

he was doing some construction work in wisonson where it was really cold. he went to turn the light on and...*nothing*...

is the battery in the ultrastinger susceptible to cold weather? if so, how about the tl?

I believe, and maybe an elec. engineer can explain better, that NiMH and Nicds are susceptible to cold weather, makes them drain faster...hence why people say that emergency workers in cold environments are better off with lithium powered lights.

Oh boy.... Roth, that guy must be thinking... Hmm... this roth-ten guy recommended me to get a light which I can't use... he must be making fun of me....

You better clear it up with him soon, you don't wanna lose another potential flashaholic.

hmmm, is there any rechargable light that works in cold enviroments?

certainly want to ruin a potential flashaholic

The chemical reaction that produces electricity in batteries is affected directly by temperature. The colder it is, the slower the reaction. Lithiums are least-affected.

Tell your friend to keep the light inside his jacket so it's warmer. I don't believe Thermos makes a rechargable flashlight, but if they did, it'd probably be the one you want.

good idea..."portable flashlight warmer" the can be sold as accessories in truckstops around the country.

I find that very interesting. I've used ni-cd batteries in still cameras at 0F with limited use below that to -40F. Alkalines would certainly die, ni-cds are better.

My research about twelve years ago indicated that a _charged_ lead acid was great at low temperatures.

And, don't be misled. Lithiums lose a lot of their power at low temperatures. A major camera manufacturer in a premium camera used 2CR5 lithiums and I would get 10-15 rolls per battery at warm temperatures, while the voltage would drop enough to have me changing batteries every three rolls around 0F.

My notes from my Photography Forum SysOp days and Outdoor Photographer article on the subject in the early 1990s indicate that nicads "maintain useable capacity" to -40.

DO NOT try and charge them cold, however. This could be a problem with a vehicle-mounted charger. They shouldn't be charged below freezing.

I am not sure how ni-MH cells do in the coldest weather.

Cheers,

Richard

Energizer's data sheets show that you get the following percentages of capacity discharging NiCads at various celcius temperatures.

20 to 35 degrees = 100%
10 degrees = 90%
0 degrees = 80 %
-10 degrees = 70 %
-20 degrees = 58 %

Nicads shouldn't be charged below 0 degrees C at the 7 to 10 hour rate or below 15 degrees C at the 1 to 3 hour rate.