[pct-l] Battery Info - temp?

[terry.norton at gmail.com (Terry Norton)]

Nathan,

You can get the Energizer battery specs at:
http://data.energizer.com
AAA Alkaline: http://data.energizer.com/PDFs/E92.pdf
AAA Lithium: http://data.energizer.com/PDFs/l92.pdf

GOOD!!! You are keeping your avalanche beacon next to your skin.  (I
teach avy classes.)  As you mention, your beacon stays warm and the
temperature effect on the battery life is minimal.

At low currents such as those used by a beacon, I don't think the
temperature effect is likely to effect beacon performance if you
follow most beacon manufacturers recommendation to replace batteries
when the life indicator is at 50-60%.  A set of batteries typically
lasts me a year with at least 20 days of use.

Beacon manufacturers recommend against using lithium batteries since
beacons are designed to detect the discharge pattern of alkaline
batteries.  The beacon will not properly indicate the charge level on
lithiums.  ( http://www.ortovox.com/typo7/index.php?id=241&L=1 )

The charts for operation under high current loads (250ma) show that
alkalines loose about 44% of their capacity at freezing (0C) compared
to 21C(70F).  At -20C (-4F), the fall off is about 84%!!!

Lithiums do excel in this area.  At 0C/freezing the loss of capacity
is about 4%, and at -20C(-4F) the drop off is only 19%.

Being a total geek (it pays), I measured the current requirement on my
Tikka at 32mA.  The effect of temperature will not be as dramatic at
this lower current.

cheers,
terry

ps:  There is an issue with some Ortovox beacons (M1 & M2) related to
battery size.  Ortovox is offering a free updated battery cover to fix
the problem.  See http://www.ortovox.com/typo7/index.php?id=58&L=1

On 3/13/06, Nathan Young <ny74@hotmail.com> wrote:
> Hey Terry
>
> Thanks for the battery details, they're right in line with what I've been
> experiencing in the field.
>
> I was wondering about temperature effects on battery life.  They say
> Lithiums can handle the cold better.  Is that true?  I haven't had the
> chance to test this on my ski tours since everything battery operated that I
> carry is usually close to my body and its warmth all the time.  My tikka
> fails mostly from frozen buttons before I can see if the battery dies, and
> my Avy becon never leaves my body.
>
>