Mercury cells

[Carlo G]

I would like to know how long for is possible to store, and in wich
conditions (temperature), the out of production mercury cells 1.35Volts
PX625.
They are infact now rare, due to the mercury contained iside that creates
enviroment contamination problems. On the other hand it is no easy to obtain
with other batteries the same perfrmances on some apparatus, due the
constant voltage output.
Considering that I still have a couple of PX625, I would like to know how
long may I expect to have them ready to work with my exposure meter Gossen
Lunasix3 that accepts also the new alkaline 625 but showing no useful
indications due the different voltage ( using two PX625 there is a
difference of plus 0.3 Volts).

Is there any serious adapter to use with different battery type? I was
thinking to choose Silver-oxide cells and do not take in consideration
air-zinc technology because of the short life of cells: less than one year,
even if you do not use the meter, from the moment you lift the label.

MOST IMPORTANT: How can I manage the mercury exausted cells? Can I put them
in the "normal" exausted batteries bin?

Thanks. Carlo

 

[Spehro Pefhany]

I would like to know how long for is possible to store, and in wich
conditions (temperature), the out of production mercury cells 1.35Volts
PX625.
They are infact now rare, due to the mercury contained iside that creates
enviroment contamination problems. On the other hand it is no easy to obtain
with other batteries the same perfrmances on some apparatus, due the
constant voltage output.
Considering that I still have a couple of PX625, I would like to know how
long may I expect to have them ready to work with my exposure meter Gossen
Lunasix3 that accepts also the new alkaline 625 but showing no useful
indications due the different voltage ( using two PX625 there is a
difference of plus 0.3 Volts).

Is there any serious adapter to use with different battery type? I was
thinking to choose Silver-oxide cells and do not take in consideration
air-zinc technology because of the short life of cells: less than one year,
even if you do not use the meter, from the moment you lift the label.

Some years back, I had a "portable potentiometer" (despite the name,
it's a voltage-output device used for calibrating thermocouple
instruments) that used mercury cells (and a standard cell for
calibration). I replaced the mercury D-cells (?) with alkalines and a
voltage regulator, which worked fine and ended the scramble to buy the
very expensive cells every year or so. The stable (and relatively low)
voltage output of the mercury cells is the characteristic that you
need to simulate.

Here's someone that's done a commercial job for your kind of battery:

http://www.smallbattery.company.org...ww.smallbattery.company.org.uk/sbc_s625px.htm

A bit pricey at ~US$55.

MOST IMPORTANT: How can I manage the mercury exausted cells? Can I put them
in the "normal" exausted batteries bin?

Thanks. Carlo

I think they should be disposed of as hazardous waste, but call your
local garbage people and ask. For home use (not industrial) there are
often places you can drop such waste for free.


Best regards,
Spehro Pefhany

 

[Dave Platt]

Is there any serious adapter to use with different battery type? I was
thinking to choose Silver-oxide cells and do not take in consideration
air-zinc technology because of the short life of cells: less than one year,
even if you do not use the meter, from the moment you lift the label.

There seem to be three approaches to this:

[1] Have your equipment modified to use alkaline 625-size cells,
and accept or compensate for the changing behavior as the
batteries age.

[2] Use the WeinCELL MRB625 zinc-air cells, which have a 1.35-volt
output level and are designed for a longer life than hearing-aid-
type zinc-air cells. One seller claims useful lifetimes of up to
2 years in some situations.

[3] Use an MR-9 adapter, which accepts a silver-oxide 386 cell and
regulates the voltage down to 1.35 volts.

You'll probably get much more stable results with approaches [2] and
[3] than with approach [1]. Approach [2] is the easiest drop-in
approach, but I can't hazard a guess as to how long these specialized
cells will remain on the market. Approach [3] is more expensive than
[2] initially but would be cheaper and perhaps more sustainable in the
long run.

Disclaimer: I haven't actually used any of these approaches yet
myself.

 

[mc]

I'm not sure what kind of equipment you're talking about, but with most
cameras, a 1N34 germanium diode in series with a silver-oxide cell (1.55 V)
provides a good, stable substitute for a mercury battery. Yes, 1N34. The
voltage drop will be 0.2V at low current, not 0.35V as theory suggests.
There are even Schottky diodes that give a stable 0.2-volt drop over a wider
current range.

Is there any serious adapter to use with different battery type? I was
thinking to choose Silver-oxide cells and do not take in consideration
air-zinc technology because of the short life of cells: less than one
year,
even if you do not use the meter, from the moment you lift the label.

There seem to be three approaches to this:

[1] Have your equipment modified to use alkaline 625-size cells,
and accept or compensate for the changing behavior as the
batteries age.

[2] Use the WeinCELL MRB625 zinc-air cells, which have a 1.35-volt
output level and are designed for a longer life than hearing-aid-
type zinc-air cells. One seller claims useful lifetimes of up to
2 years in some situations.

[3] Use an MR-9 adapter, which accepts a silver-oxide 386 cell and
regulates the voltage down to 1.35 volts.

You'll probably get much more stable results with approaches [2] and
[3] than with approach [1]. Approach [2] is the easiest drop-in
approach, but I can't hazard a guess as to how long these specialized
cells will remain on the market. Approach [3] is more expensive than
[2] initially but would be cheaper and perhaps more sustainable in the
long run.

Disclaimer: I haven't actually used any of these approaches yet
myself.

--
Dave Platt <[email protected]> AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

 

[Henry Kolesnik]

My Rollei 35 uses same battery. Walmart has zinc/air hearing aid batteries
that'll work. They won't have the same life and require a piece of
insulated wire or whatever to keep them centered as they're smaller.