Mercury battery substitutes

L.J.SILVER · Aug 26, 2009

I have just resurrected my old Canon EF and Canon F1 (from the mid-70s) which I haven't used for over 20 years. I'll be sending them for a CLA but the original specified batteries (Mercury PX 625 1.35V) are no longer available. Anyone know what can be substituted that will give accurate readings and function just like the old mercury batteries?

My apologies if this has been covered in an earlier thread but I couldn't find it. And yes, the EF along with the original F1 are in my opinion excellently constructed cameras. I stopped using them only because I switched to medium and large formats.

E76 · Aug 26, 2009

While a bit pricey, a Wein Cell should work nicely. They're zinc-air cells and have discharge properties similar to mercury batteries.

MattKing · Aug 26, 2009

hmho said:
I have just resurrected my old Canon EF and Canon F1 (from the mid-70s) which I haven't used for over 20 years. I'll be sending them for a CLA but the original specified batteries (Mercury PX 625 1.35V) are no longer available. Anyone know what can be substituted that will give accurate readings and function just like the old mercury batteries?

My apologies if this has been covered in an earlier thread but I couldn't find it. And yes, the EF along with the original F1 are in my opinion excellently constructed cameras. I stopped using them only because I switched to medium and large formats.

Here is an example of a thread that discusses this:

(there was a url link here which no longer exists)

There are lots of other threads, but as the question often comes up in relation to a particular camera, they may be hard to find.

Personally, I use an adaptor like the MR9 adaptor like the one John Hermanson sells at zuiko.com. Actually, I could use another one .

Matt

P.S. Moderators, if the answers in this thread get fleshed out a bit more, possibly it could be made a "sticky"

David A. Goldfarb · Aug 26, 2009

MattKing said:
P.S. Moderators, if the answers in this thread get fleshed out a bit more, possibly it could be made a "sticky"

Good idea. Let's see how it goes or if there's another thread on this topic that might be merged with this one to fill in the gaps.

E76 · Aug 26, 2009

I'm wondering if it might be time to establish an APUG Wiki dedicated to all things analog. I know we already have the articles section, but I think a wiki would make a great companion to it for subjects such as this.

srmcnamara · Aug 26, 2009

I know in the past that I've used hearing aid batteries in my minolta srt-201. Nowadays I just use an external meter.

L.J.SILVER · Aug 27, 2009

srmcnamara said:
I know in the past that I've used hearing aid batteries in my minolta srt-201. Nowadays I just use an external meter.

Thanks for the information. Is the Wein Cell battery 1.35V?

L.J.SILVER · Aug 27, 2009

E76 said:
While a bit pricey, a Wein Cell should work nicely. They're zinc-air cells and have discharge properties similar to mercury batteries.

(Sorry, wrong quote attached to my previous reply.)

TheFlyingCamera · Aug 27, 2009

Yes. The Wein cells are designed to be 100% compatible with the batteries they replace. They won't last the decade or so that a mercury cell would, more like a few months to a year, but they are voltage correct and stable over the life of the battery.

elekm · Aug 27, 2009

Many people (including myself) are using hearing-aid batteries with a rubber "O" ring that is used in plumbing. You can pick up a bunch for a couple of dollars. The hearing-aid batteries have decent life and are readily available. Generally, you can buy them five or 10 to a pack.

The voltage is 1.4 volts, which is close enough to the original spec of 1.35 volts.

With certain cameras, this method won't work, and it will be those cameras that require the specific shape of the old PX13/625 battery. These often have a contact point on the side of the battery chamber.

And still other cameras require a spacer. A small metallic washer works fine.

jfdupuis · Aug 27, 2009

You should look at : http://www.butkus.org/chinon/batt-adapt-us.pdf or http://ludens.cl/Electron/mercreg/mercreg.html.

The first one use only schottky diode to create an appropriate voltage drop from a silver cell. If you need two of them, then you could also use the very typical 1N4148 diode. A nice and permanent solution, is to open your camera and weld the diode on the battery compartment wire.

Denis K · Aug 27, 2009

elekm said:
Many people (including myself) are using hearing-aid batteries with a rubber "O" ring that is used in plumbing.

And still other cameras require a spacer. A small metallic washer works fine.

For those that don't mind dropping eight bucks for a precision machined metallic band that wraps around a hearing aid battery I have found this to be as close to a final solution as any other. The band is like a mens wedding band with a small slit cut through it, lets say between the 12:00 o'clock position to the 12:03 position. The slot allows it to expand ever so slightly as you wrap it around the outside of a hearing aid battery. Because it is metal, this solution will work for even those appliances that have one of the battery contacts on the side instead of on the top and bottom.

See: http://www.paulbg.com/Nikon_F_meter_batteries.htm

Recommended.

Denis K

PS: The $8 includes one hearing aid battery.

removed account4 · Aug 27, 2009

i probably shouldn't do this
but i just use the 625 cell
knowing the meter will be
a little off.

if i get a mr9 adapter
will i have to have my meter recalibrated ?

the hearing aid zinc air batteries are OK
but they die pretty quickly since you remove the tab
and air activates the battery ...

budrichard · Aug 27, 2009

Walgreens 675 Hearing Aid Battery with o-ring works just fine. Its a #9 o-ring. I use them in my Luna=Pro and can fit my Leica MR meter.
Can be had for less than $1 per battery in bulk. Pull the tab off the battery and wait for the reaction to begin before using.-Dick

jeffreyg · Aug 27, 2009

Wein cells and you may find an Energizer that will work. It's a good idea to have at least one spare and I always change my batteries on my birthday or before taking a trip if they are good or not.

CanonShot · Aug 28, 2009

Can't the mercury 1.35V battery be replaced by a silver-oxide 1.5V by recalibrating the mechanical adjustments on the camera's light meter and potentiometers?

archphoto · Aug 28, 2009

That is one way to go, the other one is to solder a scoty diode in series to bring the voltage down from 1.5V to 1.3V.
The O-ring is used so the new battery fits mechanicly.

Peter

wiltw · Aug 28, 2009

CanonShot said:
Can't the mercury 1.35V battery be replaced by a silver-oxide 1.5V by recalibrating the mechanical adjustments on the camera's light meter and potentiometers?

Absolutely not an easy thing to do. The Olympus OM-1, for example, has meter error based upon both output voltage of the battery as well as brightness of the ambient light being measured. I did a controlled experiment many years ago (using my OM-1n which I purchased new). I now use the adapter mentioned in this thread, that zuiko.com has.

eli griggs · Aug 28, 2009

I also use the Walgreens 675 in several cameras, etc. Ok life and cheap enough that I can keep a bunch of spares on hand, although it does take a few hours to get up to strength once the tab is pulled.

Eli

Tony-S · Aug 29, 2009

CanonShot said:
Can't the mercury 1.35V battery be replaced by a silver-oxide 1.5V by recalibrating the mechanical adjustments on the camera's light meter and potentiometers?

A lot of work to do and a bit expensive. You can use the 1.5V batteries, but set your ISO to 40% of your film (i.e., 40 for ISO100 film, 160 for ISO400 film, etc.).

MattKing · Aug 29, 2009

Here is a link to another related thread:

(there was a url link here which no longer exists)

Matt

Denis K · Aug 29, 2009

CanonShot said:
Can't the mercury 1.35V battery be replaced by a silver-oxide 1.5V by recalibrating the mechanical adjustments on the camera's light meter and potentiometers?

Even if you have a potentiometer the problem with non-mercury batteries is that the voltage potential of alkaline batteries drop over their life. The voltage of a mercury battery stays very stable over it service life and many camera manufacturers took advantage of this to keep from having to design in a voltage regulator. Some light meters with mercury batteries don't even have an on/off switch. They rely of the very low battery drain in darkness to provide a long battery life (so long as you keep the cover closed on the light meter when not using it.) I have an old Gossen Super Pilot that works like that. Voltage regulators that draw a small quiescent current are very difficult to design, or at least they were in those days. So even if you were willing to add one in to allow the use of non-mercury batteries it would only be a reasonable solution for those devices that have an on/off switch. Otherwise the quiescent current of the voltage regulator would run down the battery. If you search the web you will see a lot of solutions that use a series diode to drop the voltage of an alkaline battery close to the mercury battery equivalent. In fact, that merely drops the voltage by a fixed amount. It will not regulate it at a fixed voltage to simulate the mercury battery characteristics. The one thing the diode solution does have going for it is that since the diode is wired completely in series with the battery, it has zero quiescent current and so can be used without an on/off switch.

You can however use an alkaline battery and just not sweat the small stuff. You can then make a little mental adjustment in your head based on experience or adjust the ASA a smiggen on auto exposure cameras. Basically what you are doing here is saying that even with the inaccuracy, the exposure estimate might be closer to what you want than relying on the sunny-16 rule.

Denis K

johnnywalker · Aug 30, 2009

I bought an adapter from CrisCamera. Expensive, but worth it to me. See the thread Matt references.

2F/2F · Aug 30, 2009

675 1.4V hearing aid batteries are the best option, IMO. I had been using 1.5V alkaline replacements and Wein cells, and finally settled on the 675 at the recommendation of my camera repair shop. 1.5V alkalines require modification of your camera to be accurate, and Wein Cells are the most overpriced, shortest lasting, and most inconsistent batteries I have ever used in any of my cameras. I would never recommend them to anybody if there is an alternative. The meters on my several Canon bodies were never calibrated with each other for more than a day or two with either Wein Cells or 1.5V alkalines, but they are always spot on in calibration with each other until the day they die with the 675s. My meters have never been more consistent, and batteries have never been cheaper. Way better and way cheaper. What more do you need to know? You need to wrap the battery in something to make it roughly the same size as the 625 batteries. I use a split metal washer, but you can also use o rings, and I have heard that a "nest" of copper foil works as well. They last about a year for me, but I don't use my in-camera meter much.

L.J.SILVER · Aug 30, 2009

2F/2F said:
675 1.4V hearing aid batteries are the best option, IMO. I had been using 1.5V alkaline replacements and Wein cells, and finally settled on the 675 at the recommendation of my camera repair shop. . . . My meters have never been more consistent, and batteries have never been cheaper. Way better and way cheaper. What more do you need to know? You need to wrap the battery in something to make it roughly the same size as the 625 batteries. I use a split metal washer, but you can also use o rings, and I have heard that a "nest" of copper foil works as well. They last about a year for me, but I don't use my in-camera meter much.

Thanks everyone for the helpful information. I'll try the hearing aid 675 1.4V battteries with a washer.

Mercury battery substitutes

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