AA batteries and Ortovox M2 shutdown.
I just got this in e-mail from CAIC,
Quote:
Friends,
The following message came to us from the US Forest Service National Avalanche Center via the Mountain Washington Avalanche Center (NH) regarding battery-size issues for the Orotovox M2 avalanche rescue transceiver. The M2 may shut off after incurring a moderate blow. The problem has to do with battery dimensions and not the transceiver.
The gist of the following message is that AA batteries vary in size depending upon brand, and smaller-sized AA batteries can shift about causing the transceiver to shut off. To prevent a potentially serious consequence M2 users should use "the most robust AA you can find that is wide, long, and has large terminal ends." For more details, please see the message below.
Dale Atkins
Colorado Avalanche Information Center
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Quote:
Subject
AA batteries and Ortovox M2
shutdown.
You guys might find this interesting and alarming. Excuse
this memo if this is already common knowledge, but I have not heard
anything about this Ortovox M2 problem. Please pass this along through
your networks so we can get the word about this concern.
I caught wind that a couple of our local guides were having problems with
their M2 shutting off when the unit took anything more than a moderate
knock, such as striking it in your palm. Initially we thought it was the
same problem the M1's had with to much slop in the battery compartment
which Ortovox fixed with the M2. They dealt with this issue by increasing
the size of the battery pressure tabs on the inside of the compartment
door. 3 of us use M2's so we tried to duplicate the problem. We could get
the batteries to shift, but no where near enough to shut off the unit. I
was able to get hold of one of the Guide's M2 and sure enough we got the
unit to shut off. After some trouble shooting it came down to the specific
size of the batteries. After getting 6 or 7 different manufactured AA
batteries side by side they were all a bit different in size. The largest
and the smallest was actually quite substantial. The other issue was the
height of the + (positive) nub on the top of the battery as well as the -
(negative) contact on the bottom. The best battery for the M2, of the ones
we looked at, was the Duracell Coppertop due to it's large diameter and
longer length. The negative terminal also protrudes from the bottom while
many are either flush or indented. The M2 compartment tolerances are so
tight that batteries 1mm shorter or thinner at times was enough to make a
difference to shut off the unit. I was able to shut the M2 down with no
trouble with more than one manufactured battery. The original problem
battery was an Energizer alkaline and one of the smallest batteries was the
GSA contracted Kodak alkaline AA that many government employees might be
using.
I never gave much thought to the size changing from battery to battery, but
in this application the consequence could be substantial. I have some
additional thoughts about exactly why and how the small batteries fail.
Folks can call me if they want the long winded version. The short of it is
use the most robust AA you can find that is wide, long, and has large
terminal ends. Chris
Christopher P. Joosen
Lead Snow Ranger/Dispersed Recreation Supervisor
Director-Mount Washington Avalanche Center
White Mountain National Forest
