625 battery

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has anyone found a replacyment for the 625 mercury battery that realy works?

-- tom hipple (elizabethmmg@msn.come), August 30, 2001


These guys still have the real mercury cells,


as well as a PX625 silver cell that needs no adapter/O-ring, etc. The silver cells are a slightly higher voltage, and this may or may not affect the readings depending on the way the meter is designed. They work fine on the meter MR. I'd grab a few of the mercury cells and you'll be good for another 10 years.

-- Andrew Schank (aschank@flash.net), August 30, 2001.

Another alternative is to have your meter re-calibrated to take non-mercury batteries. Quality Light-Metric in LA (323-467-2265) did a great job on my Leicameter MR.

-- Chris Chen (furcafe@cris.com), August 30, 2001.

Chris, I hope they didn't charge you much to "calibrate" your meter. I have swapped the mercury cell and silver cell back and forth in my Meter Mr, and it didn't effect the readings at all.

-- Andrew Schank (aschank@flash.net), August 30, 2001.

A 1.5v battery in my MR-4 meter nearly ruined a vacation for me. Everything (Kodachrome 25) was underexposed by a half a stop until I happened to compare it to another meter. A dealer slipped me the wrong Varta battery and I didn't catch it.

I'm sticking to 1.35v mercuries as long as I can.

-- Bud (budcook@attglobal.net), August 31, 2001.

Ugh, the mercury battery. Banned now in the US and other northern countries.

May I kindly suggest that if we can find non-mercury substitutes, that is better. If not, it would be good to dispose of them carefully- while NiCd, Ni-MH, Li-ion and small sealed Pb batteries seem to be taken care of, there is at least one private vendor that recycles mercury batteries. If you are traveling from to developing countries where no such waste battery infrastructure exists, keep your spent Hg batteries with you until you can make sure they'll be properly disposed of.

Ironically, one of the great examples of photojournalism, by W. Eugene Smith, chronicled the suffering of a small Japanese fishing village that was striken by none other than mercury poisoning.

-- Tse-Sung Wu (tsesung@yahoo.com), August 31, 2001.

Best and simplest solution: the MR-9 adaptor from www.criscam.com which uses a standard MS76 silver oxide and adapts it both physically and voltage to the exact specs of the PX625. I use one in my SL.

-- Jay (infinitydt@aol.com), August 31, 2001.

Andrew: Actually, my MR was corroded & needed a complete overhaul anyway, so I had them do the calibration @ the same time (no extra charge)--it now uses the MS76 size batteries w/a metal O-ring. While I have no experience using silver oxide batteries in a non-modified MR, I've had experiences similar to Bud's, where substituting the silver batteries for mercury created a 1 or 2-stop discrepancy; not the end of the world (assuming the discrepancy was consistent & constant over time), but enough to bug me.

-- Chris Chen (furcafe@cris.com), August 31, 2001.

That's strange that the same meter would react differently to battery voltage. Couldn't you just reset the zero with the adjustment on the back of the meter? As far as mercury batteries go, I am all for environmental protection, but the ban on mercury batteries will not have any impact on the mercury levels in the environment. Electric utility coal fired power plants are the main source of mercury (in the most volatile vapor form)and still have nearly no safe gaurds in place to limit or eliminate it. In typical fashion, insignificant source of a toxin are singled out while the source of the problem is left alone.

-- Andrew Schank (aschank@flash.net), August 31, 2001.

I also first thought just changing the zero setting, or the ISO, to compensate for the difference in voltage would be sufficient. But on my SL, with a 1.5v battery the discrepancy was different at each end of the scale. Using the MR-9 adaptor, it reads accurately across the range. So too would an actual recalibration. But the cost for doing that was more than the MR-9 so I figure to wait until it needs a CLA.

-- Jay (infinitydt@aol.com), August 31, 2001.

As Andrew says the fuss of mercury batteries is a storm in a teacup. Most pollutants of this nature come from large industrial concerns which governments hate to upset and regulate as they pay large taxes and have huge clout. Also, let us be honest - they produce goods people want. A few batteries here or there does not matter.

However, having said that I think the main worry was that children were finding these batteries in tips and in the home and swallowing them (as young children are liable to do). The mercury content of a 625 battery is sufficiently high to cause concern. In contrast silver and lithium batteries are more benign.

Like Jay says, I use the MR9 convertor so the problem is over for me.

-- Robin Smith (smith_robin@hotmail.com), August 31, 2001.

Makes sense Robin, PX13's wouldn't make a very healthy suppliment.

-- Andrew Schank (aschank@flash.net), August 31, 2001.

and don't overlook the silver and gold smelters.... they've been what, "tamed down" to something like an allowable TEN POUNDS a day, of mercury.... can you imagine pumping ten pounds of this into the air every day? I would hope I read a typo and that figure is per year, not per day! So much for reclaiming or recycling something.

-- Larry Welker (lwelker@turbont.net), September 02, 2001.

Not to mention forest fires in the rockies. The Fridley fire is releasing large amounts of Hg. While the press is suprised, I'm not. It is not that far from Cinnabar Mt which is a large pile of mercury ore. :)


-- Art (AKarr90975@aol.com), September 02, 2001.

If possible just solder a 1N5711 or BAT 81 or BAT83 Schottky diode in series with the wire of the batterycompartment, then you can use Silver cells ( no Alkaline !! ). For info on how to make an MR9 adapter yourself: just e-mail me and get a free d.i.y. guide for making one.

-- Frans de Gruijter (f.p.de.gruijter@freeler.nl), November 12, 2001.

"That's strange that the same meter would react differently to battery voltage." Andrew, the CDS cell is like a variable resistor-- the resistance varying with the amount of light. When the resistance decreases, the current increases, and thus the meter registers more current (swings farther upscale). Now, if you increase the battery voltage, that will also increase the current, even for the same cell resistance (Ohm's law: current equals voltage divided by resistance). The difference between 1.35v. and 1.5v amounts to an 11 percent increase, enought to make the meter read high by perhaps 1/3 to 1/2 stop or so. The result: slight underexposure, as Bud reported.

I am finding that my Leica-Meter MR is reading about 1/2 stop high, though, even with the old PX-625 Mercury battery. With the Wein air cell, there is no difference compared to the PX-625. So I'm getting underexposure, both by comparison with the M6's meter, and by actual results with transparencies. The MR used to be quite accurate. Apparently the cell's resistance has decreased somewhat over time.

So either it's time for it to go to Quality Light-Metric, or else I'll just stick with the Wein Cells (or get an adapter) and set my film spedd 1/3 stop lower than the film's true rating.

Is anyone else having a similar experience with this meter?

-- Bob Fleischman (RFXMAIL@prodigy.net), November 12, 2001.

I suppose it is not just a matter of comparing voltages, 1.35V versus 1.5V. There are possibly a number of parameters. As different batteries drain, their voltage curves fall off differently. I am not sure, but I heard that mercury cells have the most stable voltage curve (horizontal) throughout its life span. Their internal resistances may vary too. Thus affecting current outputs. This is why there isn't really a true replacement.

-- Loo W. H. (loowh@starhub.net.sg), December 06, 2001.

Everything you want and need to know about PX625/PX13/MR9 mercury batteries and all the different solutions with pros and cons are all in an article (14 pages of info)i have written. For a free copy (in Adobe Acrobat format 290kB) please mail me.

-- Frans de Gruijter (battery.adapter@wanadoo.nl), February 20, 2002.

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