Wein cell longevity?

Just popped one in the OM-1. Anybody got specific data on its longevity? I do mean specific, or as much as possible. Saw a couple of older threads on it, but with vague references on how long they last—read from "a few months" to "nearly a year". If anybody has used them consistently for a few years and has had to change them a couple of times, I'd appreciate to know at which frequency that happened.

Thanks!

I never used a Wein cell in an OM-1, but when I had one in post-mercury cell times, I did use hearing aid batteries in an appropriate physical adapter, which employ the same zinc air battery technology, and provide the same voltage. When I wanted longer life, I also used a voltage modifying adapter that permitted use of silver oxide cells.
At the same time, I was also using hand meters with 625 cell and appropriate adapters. I still use them.
I say all this just to make clear that the zinc air battery life varies greatly, depending on application.
And with an OM-1, it will depend greatly on how you deal with turning the meter on and off.

I used them once for a Konica Auto S3 and each battery last about a couple of months. Zinc-air batteries produce electrical energy by contact with oxygen in air, so as soon as the sticker is removed the battery starts depleting (self-discharge). Opposite to other kind of batteries, it is a bad idea to remove them from the camera if they are not sealed again.

MattKing said:

And with an OM-1, it will depend greatly on how you deal with turning the meter on and off.

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halfaman said:

Zinc-air batteries produce electrical energy by contact with oxygen in air, so as soon as the sticker is removed the battery starts depleting (self-discharge).

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This is what confuses me. Does this mean that it depletes itself whether or not you turn the meter off?

I just use 625 alkaline.

Alex Benjamin said:

This is what confuses me. Does this mean that it depletes itself whether or not you turn the meter off?

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Yes

Alex Benjamin said:

This is what confuses me. Does this mean that it depletes itself whether or not you turn the meter off?

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This article should answer all your questions, and more:
https://www.butkus.org/chinon/batt-adapt-us.pdf

In my experience they last just about as long as it took me to write this. You'd be far better off using an adapter and a modern cell.

Chan Tran said:

I just use 625 alkaline.

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Discharge curve of alkaline batteries is steeper than that of Silver-oxide and Zinc-air cells. This will affect meter accuracy at different level during different stages of battery life so one can't simply adjust the ISO dial slightly to compensate.

Alex Benjamin said:

This is what confuses me. Does this mean that it depletes itself whether or not you turn the meter off?

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Correct, but inside the battery compartment not so much than leaved outside in my experience with the Konica Auto S3. On open air and unsealed the Wein Cell PX675 could be dead in 2-3 weeks.

runswithsizzers said:

This article should answer all your questions, and more:
https://www.butkus.org/chinon/batt-adapt-us.pdf

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Thanks! Exactly the info I wanted.

(This article should be a sticky...)

M-88 said:

Discharge curve of alkaline batteries is steeper than that of Silver-oxide and Zinc-air cells. This will affect meter accuracy at different level during different stages of battery life so one can't simply adjust the ISO dial slightly to compensate.

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I only use the battery in camera that must have the battery to function. Otherwise I use it without the meter.

For all my equipment requiring mercury cells, I have been using zinc/air cells. For the last 20 years or so. Here is a typical discharge curve:

Jon Goodman, of camera light seal fame, used to sell reasonably priced adapters that make use of the 675 hearing aid cells - and he is absolutely great to deal with.

Hearing aid batteries (675) are cheap, I can get from Amazon Canada 60 PowerOne brand ones for about CAD 20. As long as the sticker is on, they are probably good for 2-3 years. Once the sticker is off, they should be ok for a few days to weeks, and carrying a 6pack of those doesn't weight me down.
I just use an o-ring or aluminum foil (depending what fits better in each camera, some need some extra side contact) to fit them in, but of course a few bucks for a metal ring would work as well.

Alternatively, get an adapter with voltage conversion for silver oxide batteries (not just the simple ones without conversion circuit!), like https://www.smallbattery.company.org.uk/sbc_mr9_adapter.htm . They are sold by a couple of shops, but even more (cheap) copies without the conversion call them MR9 as well, so these should be avoided...

ant! said:

Alternatively, get an adapter with voltage conversion for silver oxide batteries (not just the simple ones without conversion circuit!), like https://www.smallbattery.company.org.uk/sbc_mr9_adapter.htm . They are sold by a couple of shops, but even more (cheap) copies without the conversion call them MR9 as well, so these should be avoided...

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I've been looking at that option—even went to Addison in Montreal to see if I could find one but they never heard of it —, but was weary about the cheap imitations. Thanks for the link. They also give info on the Wein cell:

"Another PX625 replacement is a zinc air battery. The WeinCELL MRB625 is a custom zinc/air battery designed to replace banned mercury batteries. WeinCELLs deliver the same 1.35 V voltage and stability of output as did the mercury PX625 batteries so there is no need to adjust your exposure. The WeinCELL MRB625 batteries last much longer than hearing aid batteries, some times up to a year. To achieve this longer life, the MRB625 used a proprietary electrolyte and has only two small air holes, instead of the 7 larger holes found in standard hearing aid batteries."

ic-racer said:

For all my equipment requiring mercury cells, I have been using zinc/air cells. For the last 20 years or so. Here is a typical discharge curve:

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Thanks for providing this interesting graph. I do wish the discharge curve from a mercury cell could be included for reference, but I guess that is no longer practical.

For those of use who are mostly ignorant of all things electrical, can you help us draw any practical conclusions from your data set?

I might be tempted to conclude some brands last longer than other brands, but I don't know how much variation there may be within a single brand. That is, if I bought the same brand of battery from many different sources over a period of several years, would they all produce about the same curve? Or do variations in manufacturing and/or storage conditions produce significanly different curves from a given battery? Does each line on your graph represent a single battery, or an average of results from several different batteries of the same brand?

I might be tempted to conclude that if my camera meter draws about 0.5mA, then my battery should be good for at least 225 hours. But I have no idea how much current my camera meter actually draws. And even if I did, my experience with batteries suggests there is a big difference between how long it takes to run a battery down all at once, compared to how long the battery lasts when used periodically.

I might be tempted to conclude that if a battery measures 1.2V or less, then it should definitely be replaced. But if I understand correctly, measuring battery voltage is a little tricky. Something about getting different results depending on whether or not the measuring circuit includes enough load???

I notice the batteries seem to sort as two different groups according to their starting voltages -- some closer to 1.40V and others closer to 1.48V. What I don't know is, how does the slightly higher voltage affect the meter reading? And on the other end, as the voltage drops, at what point does the meter reading become affected enough to matter -- which I think most people define as an error of about 1/2 stop?

Can you tell us anything about built-in battery testers such as the one on my Konica Autoreflex T4? At what voltage would the test light come on, or fail to light? If the the camera's built-in battery tester is reliable for mercury batteries, will it also be reliable for zinc-air and/or other battery chemistries? I assume the camera's built-in battery tester only indicates when the voltage is too low for accurate meter function -- and would not indicate a problem if the battery voltage is too high?

Finally, what is the significance of the 1.08V reference line?

Thank you, -gw

ant! said:

Alternatively, get an adapter with voltage conversion for silver oxide batteries (not just the simple ones without conversion circuit!), like https://www.smallbattery.company.org.uk/sbc_mr9_adapter.htm . They are sold by a couple of shops, but even more (cheap) copies without the conversion call them MR9 as well, so these should be avoided...

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I use this arrangement in a Rollei 35, which has no meter switch, just a black carry case to reduce battery drain. The current silver oxide battery has lasted at least 3 years.

I too have heard bad rumours about the cheap adapters you can buy on the big auction site. I can’t add any personal experience of those, but the ones sold at the link above definitely do the job.

When you don't use the camera for a longer time, you can take zink-air batteries out of the camera and take the holes shut - should discharge much slower than way.

I suggest you just bite the bullet and buy an MR-9 adapter so you can use 386 silver oxide batteries. The zincs are not worth the trouble, IMO.

Graph posted in #13 above shows:
1) The zinc cell has little voltage drop during its useful lifespan. Makes it good for a camera meter
2) The end of life characteristics are excellent. It drops voltage suddenly. Makes it good for a camera meter, as one is unlikely to get a false reading near end of life.
3) Most batteries are about the same (though they did not test a Wein brand cell). I'd like to see that comparison.
4) The life of the battery is longer than most of my photographic projects, or at lest the time it takes me to use a roll of film.

The silver cells are somewhat more of a hassle. I don't store anything with batteries in place. Silver cell camera need to have the batteries installed just like the zinc cell cameras. At least with the zinc cell cameras, the cells are always fresh. The silver cells need to be tested, since it is not economical to just throw them away after removing them from the camera, as one can do with the zinc cells.

ic-racer said:

The silver cells are somewhat more of a hassle. I don't store anything with batteries in place. Silver cell camera need to have the batteries installed just like the zinc cell cameras. At least with the zinc cell cameras, the cells are always fresh. The silver cells need to be tested, since it is not economical to just throw them away after removing them from the camera, as one can do with the zinc cells.

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Of course I don’t know how many cameras and meters you have in circulation, and thus how long it might be before you next use the current one, but this seems unduly fastidious. I’ve had zero problems with silver cells, and they seem to last a very long time whether in the camera or in reserve. I only buy well-known brands.

About different brands of battery: drawing on my life before retirement, I can assure you that there are differences, not only in best performance but also in quality control. Source is also an issue: you may get a nice cheap price because the batteries have a very short shelf life remaining.

(I have bitter experience of this: if you have 100 battery-powered units out in the field and the clock in each one depends on a (fresh) coin cell, and this is the culmination of months of preparation, it is dispiriting - to say the least - to find that most of them have failed within a couple of weeks. Fortunately I am sceptical and check more than I should need to.)

I can relate to battery concerns in high-reliability systems! Another problem with cheap and/unauthorized sources is the increased chance of counterfeit products. Not all counterfeit electronics are bad; in fact, some actually are good… but telling the difference can be a time-consuming and costly venture.

Probably less a problem with silver-oxides, but alkaline batteries leak in some devices fast, so I remove batteries as well if I don't use the thing for a while...

Where do you find your batteries are the most reliable? I have 2 cameras which use 3V CR123 lithium cells, and somehow in both cameras they drain fast. I used Energizer, Duracell and Panasonic, but without completely analyzing it, all seem to drain similarly. I mostly buy them from Amazon, in hardware stores around they cost quite a bit more and I doubt they are fresher since these are a bit more specialized then the usual AA or AAA...

snusmumriken said:

, but this seems unduly fastidious.

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Referring to removal of batteries? Removing batteries from photography equipment is pretty much a universal standard. Not only does every user's manual recommend it, if one does any camera repair work at all, one would know corroded batteries are a frustrating and preventable complication.