[Leica] Batteries in cold weather

[steve.barbour at gmail.com (Steve Barbour)]

thanks Larry, Steve


On Feb 21, 2010, at 3:55 PM, Lawrence Zeitlin wrote:

> Steve,
> I'm certainly not a battery expert. I once threw away a whole box of
> expensive silver oxide batteries that I had stored in a freezer because the
> voltage tested low when I took them out. But after a while I learned that
> the condition was normal. Most batteries based on chemical reactions appear
> to lose power when tested in cold conditions. As you recall, from basic
> chemistry, chemical reactions slow down 50% for each 10C drop in
> temperature. Batteries will fully recover power when warmed to room
> temperature. There are few camera batteries that will function adequately 
> in
> sub-freezing conditions. Here is a short paragraph cribbed from a mountain
> climbers site about the cold weather performance of batteries.
> 
> *Carbon-zinc*
> 
> These are the plain, old-fashioned batteries, and have power of 950mAh with
> a sloping discharge curve. Operating range is only down to 20degF and shelf
> life is 1/3 to 1/10th of other types - about 3.5 years. They perform very
> poorly at low temperature; at -5degF their service life is decreased by 75%
> and output drops quickly as the temperature drops below room temperature. 
> On
> the plus side, they're cheap.
> 
> *Alkaline*
> 
> The Energizer has 2850mAh and the new Energizer e2 has about 15% more, or
> 3135mAh, and both have a sloping discharge curve. Operating range is down 
> to
> 0degF and shelf life is 10+ years. They're not much better at low
> temperature; at -5degF their service life is decreased by 60% and output
> drops quickly as the temperature drops below room temperature. Although
> they're more expensive, they're comparable to carbon-zinc in terms of cost
> per hour of use.
> 
> *Silver oxide*
> 
> These are the small (dime-shaped) batteries often used in cameras and
> calculators. Since they don't come in AA size, comparative power output is
> meaningless, but they have a flat discharge curve. Operating range is down
> to 14degF and shelf life is 10+ years. They're a better at low temperature;
> at -5degF their service life is decreased by 50%. Output decreases slowly
> until about 40degF but below that output drops quickly.
> 
> *Lithium*
> 
> Lithium AAs won't outlast alkaline, with equivalent power of 2900mAh but
> with a flat discharge curve. Operating range is down to -40degF and shelf
> life is 10+ years. They're significantly better at low temperature; at
> -5degF their service life only is decreased by 20% and output decreases
> slowly as the temperature drops. They're also much more expensive.
> 
> *Rechargable batteries*
> 
> NiCads and Nickel-metal-hydrides have less storage capacity - only half 
> that
> of alkalines, they supply lower voltage, and also drain much faster by
> themselves. They do not perform well at low temperatures, roughly 
> equivalent
> to carbon-zinc.
> 
> 
> Larry Z
> 
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