Old Cameras and Mercury Batteries.

[Stan Hesketh]

Nothing new here, but just posting as it might help somebody.

I recently acquired and resurrected a Praktica SLR. It is designed to use the old mercury batteries which are now banned I believe. There are alkaline batteries that fit, but they are higher voltage and require the lens to be stopped down a couple of stops to compensate.

My hearing aids use Zinc Air batteries which are about 1.35 volts and very similar characteristics to the old mercury cells. They are however a much smaller diameter. I visited the "lucky dip" box in the shed and found some plastic spacers off a computer that I once modified. The battery was a perfect fit inside the tube, so I was able to saw a short length off and insert the hearing aid battery inside the short tube. It works a treat and keeps the battery central in the chamber. The hearing aid batteries that I use are the "orange label" type and are extremely cheap to buy. I am told that a rubber "O ring" as used in engineering works well, too. A tap washer would be another likely contender, or a piece of wooden dowel drilled to suit. I could have gone mad and bought an adapter, but it would have cost more than the camera

I need to make one for my old and trusty Chinon CS tomorrow.

Hope this helps somebody.

 

[Hamish Gill]

Brilliant!
Show us a piccy then

 

[Stan Hesketh]

Will get some tomorrow night

 

[Stan Hesketh]

As promised, here are a few (dodgy) pics:


Top pic shows left to right: Original size lithium battery, new "orange tab" hearing aid battery, plastic pipe used to make spacer, and lastly battery and spacer complete in battery cap.





The two pics compare the voltages of the lithium battery which is rather high, and the nearer to mercury lower voltage of the hearing aid battery. Sorry my shots are poor, but I needed three hands.

 

[Paul Lange]

You gotta love a bit of DIY! I always do.

 

[Pete Askew]

You need a mouth-pod! Thanks Stan, that is a great tip and I do have a couple of cameras that I could use that method for (and a ready supply of hearing-aid cells!).

 

[Stan Hesketh]

You need a mouth-pod! Thanks Stan, that is a great tip and I do have a couple of cameras that I could use that method for (and a ready supply of hearing-aid cells!).

Yes I have plenty of batteries too!
As I understand it, there are three sizes in the UK; brown, blue and orange. Orange are the smallest, but what I had to hand. I am certain that the blue ones would easily fit in the Praktica cap.

 

[Brian Moore]

Nice explanation and foties, Stan. I've been tempted on the hearing aid batteries for a couple of the old cameras but I end up just shooting manual/sunny 16.

I've read that the zinc air batts die relatively quickly. Not sure about this, but I think I also read that as the zinc airs lose power as the voltage wains. In other words, they don't provide a consistent 1.35v through the course of their life, thus the metering may be erratic over time. I'm not sure about that, though. I'll be interested to see how you get on with the zinc airs.

Do keep us updated, won't you?

 

[Stan Hesketh]

Not sure about the constant voltage (or otherwise) yet. I will take a reading periodically with the meter. I think that it would be prudent to remove these batteries when not using the camera for a period, as they can leak when exhausted. I've got to do similar in an old Chinon, so will compare results. I think a tap washer might work in this one

 

[Stan Hesketh]

Bit of an update. Got some of the Blue type batteries today (99p for six off ebay) and these fit the Praktica better than the orange type. I just put a tight fitting "0" ring around the battery to keep it central in the chamber.

 

[Doug Darter]

Hi this is my first post here. I came across the forum when I was looking for batteries a week or so ago. As a result, I posted the thread below on another forum, but I think it will be of particular interest to those here. Look forward now to posting more, on a very interesting forum.

A bit off topic, but it may be helpful nonetheless.

I have several old Nikon SLRs, including an F, F photomic, F2 photomic and F3, FA andd FE, and particularly with my earlier F photomic its been impossible for a while now to find any 1.3v mercury PX 13 button cell batteries to power the metering head. They were outlawed several years ago because of the mercury content (I wonder if anybody was ever injured by using a mercury cell?).

The only alternative was to use two smaller Wein Air hearing aid batteries with special adaptors, which was expensive, as they are life limited (about 3 months) and the adaptors are more expensive than the batteries. The PX13 had a special band about the periphery of the cell, which made contact with the metal sides of the batter tube, and more modern alkaline cells don't have this band..

I recently found a seller who is selling true to size and shape alkaline replacements for the PX 13 cells. They are 1.5 v instead of 1.3, but the Nikonians forum says that the exposure meter is not too voltage sensitive, and that a 1.5 replacement is ok.

The seller is JLS Batteries at jlsbatteries@gmail.com

The batteries were £1.55 for two, including post, which is half the price of just one converter. Two Wien batteries and two converters run at around £15!!

Hope this info is useful to someone, as he may also sell other rare batteries.

 

[Pete Askew]

Thanks Doug I'm sure that will be of interest to many here. And, of course, welcome to RPF. I'm sure you'll enjoy it here.

 

[Brian Moore]

Nice helpful post, Doug. Thank you. And welcome to RPF.