Are Zinc/Air cells, replacements for outlawed mercury batteries, erratic in their voltage output? I am using one in a Leica MR meter. When I first press the button to take a reading, the needle fluctuates erratically, but after a short time it settles down and the meter reads properly. Then it will be stable for the rest of the shoot. But when I turn it on the next day, the dance begins all over again. I tried replacing the battery but the new one does the same thing. It doesn't seem to me that the problem could be with the meter itself, otherwise why would it stabilize?

Anyone else use Zinc/Air cells in an MR meter?

-- Peter Hughes (ravenart@pacbell.net), August 08, 2001

Answers

Peter,

I've tried them in an old Alpa I'm using. Same thing happens to the meter when switched on. I think it's because the amperage is wrong, even though the voltage is (approx.) correct. It does correct itself after a time, so I guess there really isn't anything one can do about it, short of time travel.

Ah, the good old days of Mercury batteries. Who would have thought anyone would miss them?

It can't hurt the meter, but it is a pain in the butt.

-- Steve Hoffman (shoffman2@socal.rr.com), August 08, 2001.

I found zinc-air cells to be very unreliable. I never experienced what you describe, but I've gotten them dead in the box, had them die in a couple days, and had them so loose in the surrounding washer that the contact was erratic. I found a much better solution, which is the MR9 adaptor (www.criscam.com). Though there's the initial expense, the much less expensive standard MS76/SR44 silver-oxide batteries with longer lifespan end up paying for the adaptor in the long run. I use one in a Leicaflex SL and it works like a charm.

-- Jay (infinitydt@aol.com), August 08, 2001.

Don't fret, pick up the currect battery from these folks here http://www.photobattery.com/

-- Andrew Schank (aschank@flash.net), August 08, 2001.

Maybe I just got lucky but I have an old "Metra-Star" light meter made in Germany and I guess it is from the late 60's judging from the hairdos on the women in the manual and I put one of the zinc-air batteries in over a year ago and it is spot on still! It is a little hand held job with incident capabilities also and it is the only meter I use when I shoot color with my Rollieflex and it is just wonderful. The meter has a small red area that the needle moves to when u put it in test mode and it still goes right to that area. I have heard alot of bad things about these but mine is still cookin after a year plus.

Mike

-- Michael Pry (vila@techheadnetnet.com), August 09, 2001.

I hate zinc-air batteries: they are erratic and don't last long. I use the CRIS convertors in my CL and SL which converts the 625 socket to take the S76s, this is a much more satisfactory arrangement, I think. I am pretty sure it would work in an MR meter too.

-- Robin Smith (smith_robin@hotmail.com), August 09, 2001.

If you use a CRIS converter, how do you accomodate the difference in voltage (1.35v vs. 1.5v)? I once accidently put a Varta 1.5v battery in my MR-4 meter and ruined several rolls of Kodachrome before I discovered the error.

They were all underexposed.

-- Bud (budcook@attglobal.net), August 09, 2001.

Oops, I didn't realize the CRIS adaptor reduced the voltage. Sounds like a good solution.

-- Bud (budcook@attglobal.net), August 09, 2001.

Okay, I have a bone to pick here. In the photo realm we've all been hit hard by the environmentalists. It seems we're always under attack because of the waste we dump down the drain while processing, or the merury in batteries. Don't get me wrong - we all have to do some rethinking on how we use the environment, but....at a recent symposium on environmental waste I found out that in a city the size of Edmonton (Canada, where I live), population 700,000, the companies that replate automotive chrome bumpers pump more toxins into the sewage system in a month, than all the photofinisher do in a year. But does the general public know this? Of course not, because most of these companies are buried in the industrial wastelands of a city instead of in every shopping mall, as are most photofinishers. So who do the people complain about - of course that which is in front of their eyes everytime they go shopping. To bad the zealots always go after the most obvious.

-- Bob Todrick (bobtodrick@yahoo.com), August 10, 2001.

Bob

I agree with you. I think that some of the concern was also that children might swallow the mercury batteries with deleterious effects too. I think it is a storm in a teacup myself, but I suppose the answer is that if you are designing a new meter, why not use a safer more environmentally-friendly substitute?

-- Robin Smith (smith_robin@hotmail.com), August 14, 2001.

This was recently posted to the Leica Customer Forum...

"Leica Fotografie International carried an article about the Wein Cell on page 25 issue 5/2001. This zinc/air substitute for the discontinued mercury is supposed to be priced at about 8.2 Euro. The MRB624/1.35 as the Wein cell is catalogued is said to be even superior to the Old PX 625 mercuries with regards to its discharge properties. The article further stressed the possibility of galvanometer damage with the use of 1.5 V silver-oxide and warned against the use of a voltage adapter. Apparently, even though 1.35 volts is attained, errors in exposure readings are likely to happen due to the discharge characteristics of silver-oxide."

-- Bud (budcook@attglobal.net), August 14, 2001.

The resolution is that I returned the meter to the store. Strange, because it was working properly when I first tested it out, with an old mercury battery in it. But went downhill rapidly when I put the Zinc/Air cell in. BTW, I ordered a mercury battery from photobattery.com and it worked no better. By this time the meter was moribund.

-- Peter Hughes (ravenart@pacbell.net), August 14, 2001.

I use 675 HP "beeper" batteries from Radio Shack in the light meter on my Konica Autoreflex A with really good results from T400 CN and various color print films. I am fairly diligent about removing them and putting the sticker back on when the camera will sit for a while. Recently, I found www.batteryguys.com in Canada who still sell the real (mercury oxide) PX 675 for USA $2.99 each, but haven't had the time to put them on the voltmeter. These could also be sleeved up to fit a PX 625 space, but there is a small difference in amperage between them (the voltage should be 1.35 for both). On my last vacation in Germany I also accumulated a decade's supply of mercury PX 625, PX 27 and the TR 164 (some Yashica rangefinders) simply by stopping in at the oldest-looking camera and optics dealer in each small town I visited. One possible cause of the erratic meter movement with zinc/air is that the battery compartment is not sufficiently vented to allow the zinc/air battery to get the air it needs to work properly.

-- Willi Calderwood (simplicissimus@newyorkcity.com), November 29, 2001.