Mercury Battery Replacements

GeneW

GeneW

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Many of the older RF's as well as the Leica CL and Leica 5, used mercury 625 1.35V batteries now unavailable in NA and elsewhere due to environmental concerns.

What do you folks use to replace them? For my Olympus OM-1's I've been using Wein zinc-air batteries and get about 6 months service -- not bad. I've read about adapting hearing aid batteries, which are also zinc-air but cheaper than the Weins. And there's an adaper called, I think, MR-9, that takes silver oxide batteries and regulates the voltage to 1.35V.

My Leica CL still has a working meter and is still running strong on a mercury battery. But when it runs down, I'll need to replace it with something else.

I believe the Canonet GIII 17 and the Konica S3 have the same issue?

Gene
 
I am a Wein guy. It is just easy for me, they can be found at Radio Shack and Ritz Camera locations.
 
Some cameras that use mercury batteries have a circuit that accomodates variations in battery voltage. Pentax Spotmatic is an example. These will run fine on modern silver cells that fit the battery compartment.

My old Gossen Super Pilot meter also is accurate with silver cells... not sure if it has the bridge circuit or if the camera repair guy was able to calibrate it.

I've been pretty lucky this way, so far. But the Olympus 35RC will someday need a new battery, then I'll have a decision to make. Already I've pulled the battery out of the Pen FT, and just use a separate meter.

Also, some cameras can be modified by adding a diode in the meter circuit to deal with the voltage difference, then they work fine with silver batteries. This would be my choice wherever possible, I think. I use zinc-air batteries in my hearing aids, and they're a royal pain, very short life.
 
I think you hit on all the major things you can do, Gene. Personally, I tend not to rely on my built-in meters on vintage cameras and use an external meter. However, if you check the meter and it is close with a silver battery, you can try compensating by setting the film speed incorrectly (I forget if you set it higher or lower, dang).

If you are planning on using a vintage camera's meter for a long time, and you don't mind the expense, I'm told those converters work pretty well - plus, you can move it from camera to camera - I doubt if I'd buy one for EVERY camera!

Um, perhaps I should not say this - but I *have* seen the odd advert for the banned and outlawed mercury batteries. Just information for information's sake, you understand. I in no way condone that.

As mentioned, some of the older cameras DO compensate for voltage differences. I believe that the Yashica Electro series do. The Canonet, strangely enough, can be used with the adapter you mentioned, but the battery check light won't come on, although the meter will work. I am told that's because the current draw exceeds 200ma. Strange.

I have also heard of folks having their meters recalibrated by a camera repairman to use a silver cell - that might be the best long-term solution.

In the end, though - I seldom have that much faith in the built-in meters of older cameras, although often many of them are not bad. I tend to use an external meter with them.

Best Regards,

Bill Mattocks
 
A few years back, I found a source of mercury batteries and I tried to stock up enough to carry me a s long as possible. So far, so good. The 625's are now all but impossible to find, even overseas, but there are still 675's to be found.

When they're spent, the local transfer station accepts them at no cost.

However, if I have a camera that is going in for a CLA, I just have it converted to silver oxide. Case in point, one of my Olympus RD's was converted last winter to the 1.5V silver oxide battery by John Hermanson - it's part of CamTech's standard overhaul/CLA and I think it's the most stable solution for battery replacement.
 
Thanks everyone! Looks like I had the bases covered in terms of options. You'd think with so many 625 cams still operating it would be worth some battery manufacturer's time to make a 1.35v silver oxide. Ah well. I don't mind using Weins in my OM-1's cause they give me 6 months of reliable service and accurate metering. Less expensive than having the cameras recalibrated.

Gene
 
RichardS said:
You might check http://www.photobattery.com/
Type in the number of the original battery and it will show substitutes for it.

Dick
Click to expand...

Dick,

This is in no way to put you down, but there is a difference and 'acceptable substitutes' aren't really that at all.

You see, the original batteries used by most of these cameras was based on mercury and put out about 1.35 volts. Mercury batteries were good for camera meters, because they maintained their voltage for a very long time before they died - and then they died suddenly - no 'guessing' if the battery was really good or not. With me so far?

Mercury, it turns out, is bad for the environment if it gets loose in landfills and leeches into groundwater. Most governments on earth decided to ban the use of mercury in things like camera batteries for that reason.

The 'acceptable substitute' that one would get from your charts is either an alkaline 1.5 volt battery or a silver-oxide 1.5 volt battery. Both are NOT acceptable substitutes, because although they fit, they are the wrong voltage - off by just enough to throw the exposure of the camera off. And worse (for alkalines), it does not even throw them off by a predictable amount - they are all over the place. Still with me?

As it turns out, alkaline batteries start out well ABOVE the rated 1.5 volts (and even that is too high), and then drops pretty quickly. It does not have a nice level output until it dies, instead it drops and drops and drops until it is finally dead - but it may 'fool' you by lighting up your 'battery check' light until it is putting out way below what will work for your camera.

Silver oxide is a pretty stable battery - not as stable as mercury, but more stable than alkaline. But it too has a slope as it ages, and it too throws the meter off. However, many folks can compensate for the problems of silver oxide by setting the film speed intentionally wrong - just enough to compensate for the meter being off the other way. Make sense? Like throwing a ball in the wind - you aim to compensate for the wind factor.

There are also 'zinc' batteries, which work by reacting to ordinary air (therefore, they have little holes in them, and you activate them by peeling off some kind of covering over the air holes). These are often used in hearing aid batteries, among other things. They DO put out the right voltage - 1.25 volts. But depending on where you live, they die rather quickly and they cost quite a bit. Some folks use actual hearing-aid batteries with various adapters to make them physically fit in the camera, and those tend to be a bit cheaper.

You can also pay a camera repair person to recalibrate your meter to react more-or-less correctly with a silver oxide battery. Probably the best solution long-term, but even that is not perfect - the silver oxide, as mentioned, has a better 'glide slope' than the alkalines, but not as stable as the mercury - so it will go bad slowly, and leave you thinking it might be good still. You have to get used to changing batteries regularly, even if you think they are still good.

Finally, you can use an external meter, which is often the best solution - but not all older cameras will function at all without a meter in the camera and working - such as the Yashica Electro series.

So you see the dillemma. There is no easy solution, and you can't just look up the 'equivalent' battery online, because there isn't one, no matter what they say.

Of course, most modern color film has a 4-stop or tolerance, so you COULD get by with a modern replacement and no compensation in most cases - but most of us want the best performance possible from our older cameras, know what I mean?

Best Regards,

Bill Mattocks

PS - Welcome to RFF!!!
 
Actually I've been here quite a while but for some reason my original username, DickS would no longer be recognized so I had to make a slight change in it.

And I have had no problem using the substitute batteries suggested at that web site in both cameras and exposure meters.

Dick
 
Hg versus Ag2O

Hg versus Ag2O

So I did some battery experiments today, given that the Canonet QL17 came with a dead PX625 (having sat somewhere for a decade on "A"). I have the following:
- HD625 Hg battery from a Sekonics light meter I recently bought
- two 357 Ag2O batteries from my Nikon FE

The HD625 will squeeze into the Canonet and checks out with the battery test button (in the green area).

I found a plain wall where the Sekonic, the Nikon and the Canonet (with the Sekonic's battery) all agreed on exposure +/- 1/3 of a stop.

I put the 357 and a bit of aluminum foil into the Canonet and it measured the exposure as 2/3 of a stop brighter than it really is. Adjust the film speed setting accordingly, from 400 to 260, and it reads correctly.

So, although it contradits what I learnt in Chemistry, it appears that Hg = Ag2O + Al2O3 - 2/3 of a stop :D

Still, I guess the optimal solution is the Ag2O battery with a 1.25 volt Zener diode, since it will allow the battery to drop quite a bit in voltage before effecting exposure. Not sure what the discharge curve looks like but I suspect by the time a Ag2O battery gets to 1.25 volts it's dead dead dead.
 
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Hi
I've just bought a canonet G-III-QL17 and it needs a battery. Can anybody tell me what is best to buy? I have found a few on ebay, but i'm not sure whether they would be suited to the canonet. Would a zinc air battery 1.35v work alright?
Thanks, Lena
 
At work I received a new calculator ( the simple desk top type) and on the back is a warning that it contains mercury batteries and to dispose of it properly. If calculators can have mercury batteries why can't cameras? The calculator was distributed through Corporate Express and made in China (where else!).

John
 
Thankyou for the replies, I'm still trying to decide which bat to go for. Not sure about the wein cell now that some say its not long lasting. But its either that or the MR-9 adapter with silver-oxide cell. Out of those two, does anyone have an idea which one would be better in the long run? and possibly where to find the best deal on those?

Lena
 
I got a QL17 G-III Too

I got a QL17 G-III Too

lena.87 said:
Hi
I've just bought a canonet G-III-QL17 and it needs a battery. Can anybody tell me what is best to buy? I have found a few on ebay, but i'm not sure whether they would be suited to the canonet. Would a zinc air battery 1.35v work alright?
Thanks, Lena
Click to expand...

About a month ago. I put a Wein zinc-air battery in it. It seems to be working fine. Maybe 1/2 stop overesposed. That could easily be in the camera and not the battery. If the second roll of film looks overexposed, I'll adjust the ASA setting accordingly on the camera. I'm using Wein cells in my Gossen Luna-Pro as well. Everything seems fine in both the meter & the Canonet.

PS: I've had a pair of Wein batteries in a Gossen Luna-Pro since last October or November. They are working fine. I'm also careful to switch the Canonet meter OFF when I'm not using it. Good luck.
 
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Since the zinc cell is air activated, could one not cover the air holes when not in use and shut the battery down to save life? I haven't tried it, but has anyone else?
 
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