Permanent upgrade/replacement for 1.35V mercury batteries - voltage regulator

[Chan Tran]

So the user has choices...

-) use a Zn-Air cell, that deteriorates in short time after being activated (some advise to reseal it between uses)

-) use a Schottky diode adaptor/camera-modfication, with its shortcomings

-) use a complex regulator for ideal voltage stability, only as camera-modification, which needs a switch or to take out the cell between uses

There is another choice not too long ago is to use the real mercury battery. A guy in Russia was selling them but now due to the war I don't think you can get anything out of Russia any more.

 

[AgX]

Yes, or use old cells found in cameras/meters. Very few of these I still find usable.

 

[ic-racer]

Sorry, late to the thread, but is the OP offering the PC boards for sale?

 

[AgX]

-) use a complex regulator for ideal voltage stability, only as camera-modification, which needs a switch or to take out the cell between uses

In cases where originally 2 cells were used, a adapter using 1 Lithium cell might be made.

 

[runswithsizzers]

I am curious to know if any camera equipment manufacturers ever suggested any factory-approved solutions for their equipment which was designed to use mercury batteries? That is, did any companies like Canon, Fujica, Gossen, Nikon, Olympus, etc. offer to modify their gear to work with post-mercury batteries? Or did they train their service techs to do some factory-recommended modification?

 

[BrianShaw]

I am curious to know if any camera equipment manufacturers ever suggested any factory-approved solutions for their equipment which was designed to use mercury batteries? That is, did any companies like Canon, Fujica, Gossen, Nikon, Olympus, etc. offer to modify their gear to work with post-mercury batteries? Or did they train their service techs to do some factory-recommended modification?

Gossen sold a voltage-reducing adapter to use a silver oxide battery. No longer available. It works great.

 

[4season]

Sorry, late to the thread, but is the OP offering the PC boards for sale?

Search eBay for "Stable625".

 

[4season]

I am curious to know if any camera equipment manufacturers ever suggested any factory-approved solutions for their equipment which was designed to use mercury batteries? That is, did any companies like Canon, Fujica, Gossen, Nikon, Olympus, etc. offer to modify their gear to work with post-mercury batteries? Or did they train their service techs to do some factory-recommended modification?

Simple adapter sleeves, yes, from the likes of Minox, Kiev, Zenit, Alpa and others. But I'm pretty sure that no manufacturer has ever offered an active voltage regulator such as this.

 

[ic-racer]

Search eBay for "Stable625".

Found it, thank you.
Not sure where I'll use it right now as all my current 1.35v stuff runs fine on zinc cells, but it is a clever device and it will be nice to have one on hand to use in something I might buy in the future.

As I write this now I'm thinking of my Horseman film plane meter. It is pretty big so no issue placing a voltage regulator. It takes two batteries (one for high scale and one for low scale) and it would be a great project to convert to a single battery with 2 voltage regulators.

 

[Philippe-Georges]

Just to add some more information from Gossen (I suppose they know what/how to do it):

 

[AgX]

It is a hull with double base and a diode inbetween.

 

[AgX]

Something else...

Whilst for non-linearity de Gruijter explicitely advises not to use NiCad-cells (thus not going up, but instead going down with nominal voltage), this tinkerer did so nonetheless and to his own surprise found it usable in practice. He built his own charger.

PX 625

Hallo, ich habe gerade nach der Weicell PX 625 geschaut. Mit ihr komme ich am besten klar. Die vielen Adapter sind nicht so meins. Und jetzt das witzige Wittner ist preiswerter als alle Amazon Anbieter;-)

www.filmvorfuehrer.de

 

[BrianShaw]

Just to add some more information from Gossen (I suppose they know what/how to do it):

... and to supplement that...

Replacing Mercury Batteries V625PX - Gossen

The production and sale of V625PX and PX13 mercury batteries has been forbidden since 1 January 2000 by EU directive 98/101/EC, because they contain a large proportion of the hazardous substance mercury. Diese These batteries are part of the following GOSSEN exposure meters: LUNASIX, LUNASIX 3...

gossen-photo.de

 

[AgX]

That is a surprisingly well-written advice.

What makes me wonder though is that in context with their own, late electrical-adaptor they explicetely state to be unable to instead modify their old meters to take modern cells.
Maybe this statement is related to their explicite statement not to repair their old meters (including those early digital ones).

 

[qqphot]

-) one may argue that a Shottky diode introduces additional non-linearity

-) that document referred to explicetaly has it about a modifaction of the camera, even dedicated to its metering drain. Thus it is not only about an adapter solution.

I feel like in almost every case it's good luck when the schottky diode drop approach works, because for every diode the nonlinear region (i.e., constant voltage drop) doesn't begin until a certain amount of current is drawn, and doesn't necessarily begin abruptly even then. So unless the meter mechanism draws a decent current there's usually some combination of constant voltage drop and current-dependent resistive drop. It seems like it works ok on some metering mechanisms and very poorly on others.

If I wanted to permanently modify a camera and there were an easy way to access switched power, such as on the Leica CL where it's only on when the wind lever is flipped outward, I'd definitely choose a fixed three-wire regulator for the much greater precision and the fact that it can be adjusted.

Without switched power, I don't think I'd choose this solution because the constant drain would irk me, even if it's quite minimal.

 

[AgX]

De Gruijter advised to chose the diode depending on the current-draw of the meter. However that current, at least for photo-resistors depends on the illumination of the sensor...
But you indicate that the issue is even more complicated.

 

[ic-racer]

A question about the voltage regulator. Do you need to connect the ground?

 

[koraks]

A question about the voltage regulator. Do you need to connect the ground?

On a typical 3-pole regulator, yes. It needs to reference somehow.

 

[guangong]

Gossen sold a voltage-reducing adapter to use a silver oxide battery. No longer available. It works great.

It is available at B&H. Still made by Gossen for Luna-Pro meters.

 

[BrianShaw]

It is available at B&H. Still made by Gossen for Luna-Pro meters.

Thanks for updating that post. I forgot to do that myself. Yes, Gossen re-released their adapter… great news for users of their old meters!

 

[Bill Burk]

I put one of Filip’s regulators in a Gossen Luna Pro, and I have a Gossen Luna Pro with factory adaptation.

It was an adventure rigging a switch (disk inserted switch from an old Zip drive) to engage mechanically with the needle trap lever because electricity routes three ways from the battery (there isn’t one “on” switch to piggyback).

 

[ic-racer]

On a typical 3-pole regulator, yes. It needs to reference somehow.

Yes, it is totally different than a Schottky, which is too bad. I was planning on installing the voltage regulator in an OM-1, but that camera has a positive ground.
Way too cumbersome to install as the voltage regulator would need to go between the metal battery cap and the battery.

OM-1 is pretty popular and I believe the Schottky is a tried-and-true solution. Just need to make sure I get the right one.

 

[Chan Tran]

A 3 pole regulator would draw current even if the camera is drawing no current. So you would have to remove the battery when you don't use the camera. A zener in parallel is also drawing current when not in use. It would draw at least the same as what the camera needs to operate. A zener in series does not but it only drops a fixed voltage thus the voltage of the battery that you use can be higher than what the camera needs but it has to be stable.

 

[koraks]

a positive ground.

Er?
Anyway, a camera doesn't really have ground as such, unless it's somehow grounded. Doesn't matter; there's always a virtual ground. That's all that's needed. I can see how it may be mechanically challenging to connect something inside a cameraut electrically, it's really no different from any other device.

A zener in series

That would be a really odd contraption.
If using a zener (which is a bad idea here to begin with), your use it in series with a suitable resistor, the load (camera) parallel to the zener and the virtual ground and top pole of the resistor connected to the battery.
If connecting a diode in series here it would typically be a Schottky, not a zener.
Zener diodes are generally pretty awful in terms of consistency and load regulation in an application like this. They're also wasteful because of the reason you described.

A 3-pole regulator makes good sense if it can be connected after an on/off switch. Otherwise it will indeed slowly drain the battery. How rapidly this happens depends on the regulator used.

 

[ic-racer]

Er?
Anyway, a camera doesn't really have ground as such, unless it's somehow grounded. Doesn't matter; there's always a virtual ground. That's all that's needed. I can see how it may be mechanically challenging to connect something inside a cameraut electrically, it's really no different from any other device.

Yes, the chassis or all the metal structures of the OM-1 are positive. The voltage regulator would need to go between the battery and the metal battery cap and of course ground to the negative wire coming off the battery holder.
So then one is back to trying to get the regulator between the case of the 386 silver cell and the larger adapter which contacts the metal battery cap. I don't know if anyone has succeeded in getting a voltage regulator in such a small place, but, indeed a diode fits there. But for the OM-1, a diode can more easily be placed on the negative wire coming off the battery, rather than needing to cram it between the positive case of the 386 silver cell and the battery adapter which contacts the metal battery cap.