FallisPhoto
Veteran
JeremyLangford said:How long should one of those last?
You really need to go back and read my first post -- the long one.
A Wein cell is a zinc/air battery, but how long a zinc/air battery lasts has nothing to do with the solution I proposed. What I proposed was to dig the middle out of the battery, so you only have metal (it isn't a battery anymore, just a shell). Into the hole, where you dug the middle out, you put a #675 silver oxide battery. It is 1.5 volts and can last in a camera about as long as it can last in a wristwatch or anything else (about a year, with normal use). All the shell of the Wein cell does is make the smaller #675 battery fit right. However, one of the other posters says that there is a company that has started making #625 silver oxide batteries again (Duracell and Energizer stopped making them years ago). This means you don't have to gut a Wein cell to make an adapter but can just drop in a #625 silver oxide battery (it is already the right size). If your camera has been calibrated for 1.5 volts, this will be the perfect solution.
The Varta #625A battery, that the repairman recommended, is also a 1.5 volt battery, but it won't work right for more than a week or two. He has apparently only understood half of the problem (getting something in there that will fit and is close to the right voltage). He has failed to take voltage curves into account though. The reason it won't work right is because, as time goes by, an alkaline battery steadily loses voltage. After two weeks, it might have dropped to 1.3 volts. The next week, it might have dropped to 1.2 volts, and so on. Since the meter relies on a steady constant voltage for accuracy, your meter will become more and more innaccurate, and how inaccurate will depend on the light level. In low light, after about a month, it will be really wildly off, although it will maybe only be a little off in strong light.
Silver oxide batteries, unlike alkaline batteries, supply a steady, constant voltage right up until they abruptly die and that is what he should have put in there.
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