[Leica] Mercury battery solution for M5, Leicaflex, etc.??

[jbcollier at shaw.ca (John Collier)]

Silver 1.5v cells have a similar voltage stability over their useful  
life as mercury cells. You are right that alkaline cells are a poor  
choice.

John Collier

On 7-Oct-05, at 7:40 AM, Simon PJ wrote:

> Thanks for this information, Didier.
>
> I vaguely remember a potential problem to do with the voltage  
> stability of
> alkaline batteries compared to the mercury batteries: that the mercury
> batteries retain a relatively steady voltage until they fail, while  
> the
> alkaline batteries are constantly reducing in voltage. Presumably  
> this is
> something that the meter electronics have to be able to compensate  
> for, and
> may be a potential problem for the M5, Leicaflex, etc. in which the  
> meter
> circuits were designed to deal with a constant 1.35V
>
> It's quite likely that I have remembered this wrongly, and invented  
> the
> problem!
>
>
> On 7/10/05 12:40 pm, "Didier Ludwig" <rangefinder@screengang.com>  
> wrote:
>
>
>> All "new" mercury batteries I had went down after a short time.  
>> The best is to
>> modify the camera's battery tray from 1.35V to 1.5V for the newer  
>> alkaline
>> batteries (there are some in the PX625 size). The job is to solder  
>> a little
>> electric resistance module that reduces the voltage for 0.15V. I  
>> had let this
>> done with a Konica Auto-S3 and a Rollei XF 35, for CHF20 ($16 or  
>> ?9) each
>> camera. Before that I had used the 1.5V batteries and corrected it  
>> with the
>> ISO setting (don't remember how much, I had compared it to my M6's
>> lightmeter).
>>
>> Weincell has alternative 1.35V mercury-free batteries, but they  
>> are quite
>> expensive.
>>
>>> Is it still possible to get hold of 'fresh' mercury batteries for  
>>> the
>>> cameras?