What you get is the perfect solution to the no longer available PX-13 mercury battery. For $19.95 you will receive an exact fit, reusable adapter and 2 675 1.35 volt zinc./air batteries.  Simply remove the seal and press the battery into the shell, install battery into your camera and away you go. You can even remove the battery, from the adapter, replace the seal and the battery will last for years.

Having repaired cameras for over 30 years I have heard of and investigated every possible solution to the ever vexing problem of what to use in place of the no longer available PX-13 mercury battery. And although some of these solutions appeared to work, all have had short comings, were expensive and a few just plain do not work. I have listed a few and why they don't work

• PX-625u alkaline battery

  • The worst possible choice! Beside being too high a voltage these batteries are highly unstable and have a very inconsistent voltage output. There is no way to adjust or modify a camera's meter to read correctly with an alkaline battery as the error is non-linear and ever changing as the alkaline battery ages.

   

• Wein 625 Cell

  • A reasonable choice and it does have a consistent output but it is expensive and will not fit properly into many cameras. This battery is simply a zinc/air battery with a metal washer force fitted onto it. On some cameras this ring is either to high or too low to sit in the battery chamber properly and a poor or no contact is made.

   

• An adapter that uses a silver oxide battery and a schottkey or zeiner diode to control voltage.

  • Sounds good on paper but not so good in practice. This solution works on the principle that there is a slight voltage drop across one of these diodes and if you select carefully you can find one that will drop the silver oxide battery's 1.55 volts down to the proper 1.35 volts. The only problem is that as the load on the battery increases or decreases, the voltage drop varies. There is also the fact that different cameras place different loads on the battery also varying the voltage. So there is no way you can assure your meter's accuracy as the voltage is constantly fluctuating. Also these adapters are very expensive but they are reusable if a bit fragile.
     

• Having your camera modified to accept an alkaline battery

  • All of the problems above and then some.

After giving the problem a lot of thought which included ideas such as installing a solid state voltage regulator--to big and complicated--into the camera, Occum's razor slashed and true to point the simplest solution is the best.

THE SOLUTION

Although simple in concept actually doing it proved a bit bit more difficult to execute. The idea was to simply gut a PX-625U and press in a 675 zinc/air battery--perfection in simplicity.  The zinc/air battery is highly stable and has the exact 1.35 volts necessary to give accurate meter readings and once pressed into the shell of a PX-625U a perfect fit. Easy huh, and right about now your thinking  why, I'll just do this myself, well not so fast; as I said, simple in concept but difficult in execution:

• The PX-625U is filled with highly corrosive material. Trust me it will burn you.

• The shell is made out of steel and is not so easy to cut.

• The cut must be precise so good contact is maintained.

• You probably do not have the necessary tools.

• You have to design a small circular, non-marring clamp to hold the battery.

• If you factor in the cost of the batteries, remember there are 3 batteries, you would have to agree my price is pretty cheap.

• If you are going to make only one it's going to take you at least 1 hour to make properly, most likely quite a bit more.

• The only way to be sure every trace of the corrosive material is removed is to ultrasonically clean the shell. If you do not get every bit of the alkaline material out, damage to your camera can result.

• Don't be cheap my  adapter is only $19.95 and comes with 2 zinc/air 675 inserts. This set should last you years before you have to buy another cheap 675 zinc/air insert, the adapter shell will last forever.