PX625 Mercury Battery alive!

[alternative photography]

Hello,

<p>I have a collection of more than 20 Compact Range Finder Film

Cameras that use PX625 Mercury Cell. And you know a lot of them have

very good optic and the metering will still perform if Mercury Cells

are available. These cameras are like a tank. I was going to make

myself a plastic CNC adaptor with simple circuitry to regulate the

very stable SR44?s 1.55V to 1.35V. However, after a second thought, I

was wondering is it worth doing something like making this adaptor

Cell available in quantity? Instead of using CNC to make it I can

design a mold and use plastic injection to make thousands of them.

And use it to wrap around the circuitry board I design and the SR44

button cell. By doing in plastic injection housing, it will reduce

the unit cost greatly and make it much cheaper than the M9 adaptor.

<p>If anyone would share, can you let me know whether there is still

a demand in the market? Or what pricing will you buy? The product

will be in exact dimension and look of the PX625 except it is in

plastic. All contacts will be in Metal though.

<p>I really have a passion to bring this PX625 alive and so that many

of us can enjoy the cameras again. On top of that, this is something

really easy for me to do because I own a litter CNC, tooling and

plastic injection facility.

<p>All opinion is welcome. If you want to contact me in person please

write me an email at taiyenchung@yahoo.com. I would like to make sure

it is something worth doing and spend a few thousand dollars for the

mold alone.

[jsbc]

I'll be interested in 5 if price is reasonable.

[back_alley_.]

sounds worthwhile to me.

i'd use a couple.

 

joe

[alan_gage]

I'd probably be willing to pay around $10 for one; but at the time I only have one camera that would need it. If I had many cameras that would get a little expensive at $10 a pop.

 

I'd tend to think that not many people would buy more then 3 or 4 of them (I'm using my $10 cost for this assumption), even if they had 20 cameras that needed them. Rather they'd buy a few of the batteries and swap them from camera to camera as needed since they aren't likely to take out more then 2 or 3 during a days shooting.

 

Anything over more then $2 or $3 and that's what I'd envision...not that I have anything firm to base that off of nor do I know a thing about marketing. Just something for you to consider as a possible situation since that's what I'd do personally.

 

Alan

[daniel_cytron]

I'd buy a couple if they were around $10.

[summitar]

I would buy at least 10 for starters, depending on the price, stability, and lifetime of the batteries.

[awahlster]

Would the battery in the adapter be replacable? if no then you would have a hard time getting more then about the $10.00 price others have mentioned. If the silver Oxide cell was replaceable then you would be able to get more like $25.00 but would sell fewer.

 

There was a guy on ebay who sold a whole Pallet ov the origional mercury cells and he sold out in less then two years. That was a huge number of batteries. I would think that by advertising through ebay sales and a few select camera publications you could sell at a pretty seady rate.

 

As you say there are zillions of cameras that use this batteries and it seams everyone is looking for a better solution to the problem.

[dan_fromm1]

Here http://www.criscam.com/mr9.htm is part of what you'll be competing against. In addition, Bogen sells a two-cell adapter for Gossen LunaSix/LunaPro light meters that works fairly well in other applications. Their price is around $US 20.

 

Another consideration. I understand that SR-44 conversions don't work well in some cameras' metering systems, e.g., Nikon F Photomic heads, because they can't deliver the current required. Look into it.

 

And yes, if the price is around $5/cell for disposables I can use some. My Minolta Flash Meter -- original version -- takes five cells, eats them too rapidly. If the price were around $7-10/cell for ones whose SR-44 could be replaced, I can use some too.

 

Good luck,

 

Dan

[tom_s.]

I got so sick of the 625 battery issue, that I sprung for a Gossen Digiflash meter and ignore the internal metering in old cameras. My exposure is much more accurate that way, and it's generally improved the quality of my photography by forcing me to think about incident light, lighting ratios, and such.

[david_goldfarb]

If you can make a battery for the same price as the Weincell 625 replacement that lasts three times as long, I'd say there's a market (presuming the adapter isn't easily hackable--in which case you should just sell the adapter and price it as an adapter).

[._._z]

You can buy them online for $5 plus shipping.

[dan_fromm1]

OK, .[. Z, what can I buy online, and where?

[unohuu]

I have two cameras that use them; would be willing to pay approx $5 - 10 each depending on the sophistication of the gadgetry and electronics and some sense of what, if any, impact on the meter of those two cameras.

Luke

[._._z]

Dan, px625.com used to have them but he sold out.

 

Try looking at some of the top 20 results here for starters:

 

http://www.google.com/search?tab=gw&q=px625+1.35v

[randyjay]

I've got 27 cameras that take that battery. MAKE THEM!!!<p>Randy Jay

[gerald_widen]

Luckily I purchased 3 or the original mercury batteries a year ago on the internet but they don't seem to be around anymore. The companies that used to carry them seem to have sold out. Luckily they last at least 10 years of moderate use in my MR4 meter.

[stwrtertbsratbs5]

I'll buy a few.

[walter_degroot]

it seems too simple just to suggest that the asa/iso setting be altered or adjusted and then the camera reading checked with a good meter..

sure the silver-oxide has the proper discharge charateristics. ( flat and no change over the life if the cell)BUT the wrong voltage.. and the alkaline " replacement" has a somewhat closer voltage rating but the WRONG discharge charateristics. sloping discharge and never the right exposure. Some cameras use a bridge circuit and an alkaline cell may acually work fairly well as the ciruit is fairly insensitive to voltage changes,

Most older cameras use a series circuit and the voltage is VERY critical and important, the basis of correct ecposure.

as i understand it the CRIS adapter uses a resistive element to drop the voltage while using a constant voltage silver cell. Good in theory but as the light changes and the voltage to the meter changes the current also changes and the meter is then a bit off. a resistor will not work properly. The Dutch scheme uses a shottky diode that has a fixed VOLTAGE drop. and is therefore more stable. All semiconductor junctions have a more or less fixed drop . for example silicon is 0.6v . It does vary slightly with current but very slightly.

the shottky diode has a low drop across the junction and seems almost ideal for the purpose of replacing a 1.35v mercury cell with a 1.6v silver cell. I do an end run by using hearing aid cells, similar to the wein cells but much cheaper. and unfortunately , they are not available in the flanged cell shape. my canonet 28 requires a piece of aluminum foil so the smaller 675 button cell will make contact.

Moderator!! if you don't understand this DON'T delete it. Ignorance is no excuse! bounce it off others and YOU WILL SEE i have made very valid points. bottom line 1) mecanical adapter using a hearing aid cell. or a similar adapter using a shottky diods and a silver cell.

please NO resistive voltage dropping adapters. They will introduce an error. older cameras, in many ways, are superior to new ones.

[ben z]

Walter is correct. The Pentax Spotmatics I have all work the same with 1.5v as with 1.3v due to the way the meter is designed is self-regulating. Likewise I know several people who spent $60 for pairs of CRIS MR9 for their Nikon Photomics only to find that they did not read correctly over the full range of the meter. I myself brought back four Leicameter MR4s from the dead, calibrated them all (adjusted the pots) to a new PX625A (measured at nominal 1.5v), then tried a CRIS and a Wein Cell and a NOS PX625 and they all read within 1/3 stop of each other. And the CRIS is thicker so the fragile battery door was being stressed. Some repair shops will recalibrate some cameras for less than the cost of a CRIS. And the cheapest solution are the hearing aid zinc-air batteries which cost about $1 apeice in packs at Costco or Sams Club. With some washers they can be fit to about any camera or meter. If you only peel off the tape to uncover one of the holes they work fine and last longer. Take them out and tape over the hole when you're finished and they last longer still.

[david_m]

I would pay $5 for a mercury battery replacement if it was guaranteed to last at least a year. I would never pay $10. Back when you could get mercury batteries they were $1-2 and they lasted 5 years or more. My only use for them now is for a Gossen Super Pilot light meter which needs two of them. For cameras, I use an external selenium meter. Its much more accurate than any in-camera meter. By the way there were other mercury batteries than the PX625. The PX400 and PX675 were also used by lots of cameras (e.g. Spotmatics).

 

I think the scare over mercury batteries was the biggest con ever unleashed on the public. People are being buried in the ground every day with mercury fillings in their teeth. There are more harmful materials in the average TV (hundreds of thousands go in landfills every year) than in dozens of mercury batteries.

[gerald_widen]

I find the mercury batteries last about 10 years in my Leica Meter. If it used another type of battery I would probably use between 5 and 10 in that time. That seems like a lot more pollution to me.

[kelly_flanigan1]

adapters like this have been around for at least a decade. Some actually drop a 1.5V to a regulated 1.35 volts; thru a low drop special IC; that needs little voltage headroom to regulate. I remember these in the photomagazines; and also in Japan during a trip back in 1992. <BR><BR>Before you jump on this old new idea; you might want to see if folks are still selling the adapters; with paid for tooling.<BR><BR><i>Re: "The product will be in exact dimension and look of the PX625 except it is in plastic. All contacts will be in Metal though"</i><BR><BR> The one I use was about 15 bucks back in 1992; and still works today. It uses a smaller size 1.5 battery; and allows room for the IC. I got it in the Camera district in Tokyo; and it had a mystery brand name packaging. My pair is used in a LunaPro; or single in a Nikkormat FTn.<BR><BR>Since this product has already been invented; and marketed; one wonders if there are patents to expire; maybe in 5 years?

[alternative photography]

Thank you everyone for sharing. I learned that from a lot of you that it may have risk to invest into the project. But I think I would like to try my best to bring the PX625 alive again. I think the issue here is how I can reduct the cost until it is not hurting my pocket to justify. Can someone know where I can download the Mechanical drawing and Specification of PX625 and SR44? I've them measureed already but found that the measurements are quite different from various Manufacturer.

[dan_fromm2]

http://www.rolleiclub.nl/batt-adapt-US.pdf