Rangfinder batteries

[Norman Hart]

Hi
I have several old rangefinder cameras that would have used the Mercury 625
cells,which are not easily obtainable. Recently I have made an adaptor that will enable the use of the 1.4 volt ZA 675 hearing aid cell. as one has to remove a plastic seal on these cells before use can anyone give me any idea of the duration that these cells will last and wether thay discharge when not in use once opened

Regards Norman

 

[wclavey]

I find that zinc air batteries last me about 30-45 days before they have to be replaced... not because I drain the power but because that seems to be the life of a zinc air cell. Until the very end, the voltage seems to be very constant (good for light meter reading) and the current delivery remains strong, but then it goes quickly. I have not figured out why I get variation in the life of roughly 50%, unless it is a combination of both the current drain and the normal life span.

So I buy the packs of multiple batteries and I simply chek the voltage each time before I start using the meter or camera... if it is not exactly where it was the previous time I used the device, I assume I have run out of life for that cell and replace it.

 

[Gatsby1923]

In my old Yashica Electro I used a 6volt battery that went with my Canon A1. It was a 6V silver oxide battery (Eveready No. 544, UCAR No. 544, JIS 4G13, Mallory PX28) or alkaline manganese battery (Eveready No. 537, UCAR No. 537, Mallory 7K34). It was smaller than the 6 volt battery that it was designed for but I put a spring from an old flashlight battery compartment behind the battery and it all worked great.

 

[Gerald Koch]

I believe that the zinc-air batteries will last longer if you cover the air holes when the batteries are not in use. A piece of black electrical tape works. This information came from Wein.

I more salisfactory solution as far as ease of use is to make/buy a convertor in order to use silver oxide batteries. If you are handy with a soldering iron a 1N34A diode will lower the voltage of a silver battery down to the proper voltage to replace a mercury battery. Remove the baseplate and solder the diode in series to the battery holder. For cameras that use more than one battery a Schottky diode should be used. Many electronic suppliers sell 1N34A diodes for less than a dollar and I have seen them offered for as little as 5 cents in bulk.

www.criscam.com sells a nice convertor. I have several and they work very well.

 

[mgb74]

I've read that sealing all but one of the holes (with tape or nail polish) will extend the life of zinc air batteries. It reduces the current, but not enough to impact most meters. No direct experience with this method though.

 

[Donald Boyd]

Forget the zinc air batteries. They die too quickly. Get the silver oxide kind.

 

[Norman Hart]

Thanks very much for the info chaps.I will try MGB74s method of sealing a hole or two and see if it increases the battery longevity.If not it may be better to try Geralds zinc oxide with the diode. What voltage are the the silver oxide batteries or will they also require a diode in series.

Norman

 

[michaelosullivan]

Rangefinder batteries reply

Hello,

Try this link:- http:/www.smallbattery.company.org.uk/



Regards,

Michael.

 

[elekm]

If you use a zinc-air cell, there is no need to adjust the voltage. The difference between 1.35 volts and 1.4 volts is insignificant, especially when you factor in the variance of most shutters, exposure that might be off by 1/3 of a stop or more and other factors.

Most cells that I have had seem to last about 60 days. Some have gone longer and some less, so I would say that if you get two months out of a cell, that's pretty good.

Some of these cells come in a pack of five or more, and you can use small rubber O-rings to fit them into the 625 batter chamber.

 

[Norman Hart]

Thanks Chaps
I have been using the Hearing aid batteries and they work fine.I will let you all know when the first one expires
Regards Norman

 

[Lee L]

Unusually low or high humidity can shorten the life of a zinc-air battery. Ray-O-Vac recommends re-covering the air holes if used in intermittent service over more than 30 days or so and in low or high humidity.

http://www.audiologyonline.com/askexpert/display_question.asp?question_id=175

So zinc-air battery life varies with the environment the camera is in.

Lee

 

[Steve Bellayr]

Check with www.criscam.com They have an MR-9 that may be helpful. It was for my Rollei 35.

 

[smileyguy]

This is a timely thread and I'm very curious to see other's results with their batteries. I have a Konica Auto S3 that I got a new battery for in October of 2005 and I think it jus went dead in the last few days. Seems to be sudden thing in this case but was surprised to see that folks are getting only a couple of months out of their batteries.

My replacement was one of the ones that Henry's (Canada) sells to specifically replace the mercury batteries. I was going to start a thread about battery life for these cells but now I'll just go get a replacement.