Battery for the original QL17 NOT the GIII

Discussion in 'Classic Manual Cameras' started by Bleedinggumsmurphy, Feb 4, 2018.

  1. The best way to solve this problem in your camera or any one that required the 625 1.35v batteries is to install a $0.50 diode inside the camera in series with the positive battery terminal. If you don't know which end of a soldering iron to hold, you can have this mod done by your camera tech. Then you can buy all the commercially available 1.5v 625s you want for cheap (not like the Wein which is 3xs the price and only lasts 6 months). Did this to my Nikon Fs and the diode steps the voltage down to approximately 1.38. Its the way to go and its permanent, needs no adapters, foil, wrong batteries, etc. The diode part number is 1N5711 or equivalent. There are lots of different diodes that will accomplish the same results. I got mine at Radio Shack just before they closed.

    Here is just one place to get them. (no affiliation - I am just trying to illustrate how available this solution is.)
  2. Great that the LR44 works for you. You might want to look for the SR44 to get consistent voltage and longer life. This would be the Silver Oxide version of the Alkaline LR44. Just a thought.
    Bleedinggumsmurphy likes this.
  3. My preference is for the much more stable "silver oxide" batteries.
    That said, one should either acquire a reusable washer to slip over the "silver" battery for a 1.5V output, or
    the highly recommended step-down adapter.<<< click
    Further comments on battery choices are here: Silver, Alkaline & Zinc-Air batteries <<< click & scroll down for my input...
  4. If only someone could make a flat diode that would fit between a silver cell and one of the battery terminals to reduce the voltage.
  5. Looking at photos of QL 17 it looks like an easy job removing the bottom cover (two screws). Locating the positive battery wire should be pretty simple too since the battery compartment is in the bottom of the camera. I suspect there is ample space in there to permanently locate and solder in a diode (they are about as small as a grain of rice)
  6. You can also get adapters from He has them in stock and they cost around 16 Euro each if paid via PayPal. Shoot him an email to confirm availability.

    Frans de Gruijter
    Zuidkade 161
    NL-2741 JJ Waddinxveen
    The Netherlands
  7. For my purposes, the 675 zinc-air hearing aid battery is the way to go. It's dirt cheap (I buy a card of 48 of them for less than $10 at Costco) and fits just fine in all my cameras and external meters that used the old mercury 625.

    Usually with these cameras, the contacts are the top and bottom and often there's a spring to keep the battery snug up against the contacts. I find that this spring also does a good job of centering the undersized 675s, so I usually don't need an o-ring to keep it centered.

    For cameras that have the contacts for the side of the battery, like my old Nikon F, for example, getting a ring that fits the outside of the 675 is the way to go. Jon Goodman and others sell the ring for cheap enough. As mentioned above, it's possible to knock a Wein cell out of its ring, so you can use that one just as easily.

    I prefer these methods over soldering in a diode. Mostly the reason is because I own probably close to a dozen cameras that took the old mercury battery, and I just don't feel like having to do all the dismantling and soldering involved. Not when I can often just insert a battery and go.

    I don't think it was mentioned above, so I'll go ahead and mention it now. One of the nice aspects of the old mercury batteries is its totally flat discharge curve. The 675 hearing aid battery mimics this discharge curve perfectly. So does the silver oxide type, from what I've read. But the SO battery does not have the correct voltage. The alkalines, on the other hand, have a sharply peaked discharge curve and I don't consider them to be reliable enough to be used for metering purposes.

    It's worth mentioning that some cameras have a bridge circuit, in which case, a 1.5 volt battery will work reliably. Cameras like the old Pentaxes (KX for example), and the Canon EF have bridge circuits, so they can use the 1.5v silver oxide batteries and will still have accurate meters. But the Canon QL17 doesn't have a bridge circuit, so it will need a 675 or adjustment.
    marc_bergman|1 likes this.

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