Chris Crawford wrote:
> I have been using the Engergizer 357/303 batteries the last couple years
> when I was living in New Mexico and never saw any problems with them. After
> moving back to northern Indiana, I took my two OM-4T bodies out on a very
> cold day to photograph an old building, and the batteries died within ten
> minutes of going out in the cold. After I got home and they warmed up, they
> worked again.
>
> I have two questions if anyone on the list knows:
>
> Do the batteries that Bill is offering work better in cold weather.
>
Yes and no. All silver oxide button batteries will have similar low
temperature service characteristics. It's the chemistry. Service life
drops to about half at -20C. But... For the use at hand, service life is
shorter than they say to begin with, as below. Cold kills them off
quickly, which is why there have been various battery solutions for the
cold involving batteries kept inside clothing and connected to the
camera by wire.
> And
>
> I was looking at the Energizer website and they mention an EPX76 battery
> that they say is designed specifically for cameras. Their data sheet shows
> it has a higher amperage than the 357/303. I went and bought some of these
> batteries at a local store but they are EXPENSIVE. $4.50 EACH. Has anyone
> tried these in their OM's, and do they work better than the 357/303 and are
> the Sony batteries that Bill has better or the same as these? If they're
> equal or better I'll get some from him, given how cheap they are compared to
> the engergizer EPX76 bought locally.
>
You are being fooled by a label which is about different things than
what you need. "For photo use" in the battery marketing world mostly
means high total capacity and relatively quick recovery from high
transient loads. Those are not the key characteristics for OM ( and
other brand SLRs from the same era.) What you want is the longest life
without significant drop in voltage under brief high drain, as is
imposed by shutter magnets. The key phrase on Energizer sheets is
"Designed for use on low continuous drain (operating the meter) High
plse on demand (operating the shutter).
However, that doesn't mean as much as the shape of the discharge curve.
If you look at the spec sheets, you will see that the EPX76 is just a
slightly higher capacity version of the 357/303. Both have a life, with
flat voltage, under standard test load, of about 400 hrs. The 357/303H
life is about 600 hrs.
If you get any more useful life out of EPX76s than 357/303 batteries in
OM use, it will be minimal.
I believe the batteries Bill is selling will be similar to the 357/303H.
The Sony SR44W/357 and the old Energizer 357 were the best performers.
One hopes the 303/357H is a revival of the old 357. Looks like it from
the spec sheet.
So, yes the batteries Bill is selling are better than either of the
battery types you have. And no, they still won't last long in real cold.
Moose
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