Rollei 35 SE battery

[jschrader]

I just wanted to reactivate my old Rollei and found the battery dead. Since it is a PX27 mercury cell (5.6 V), it is not available any more.

On internet I found that there is a similar sized 6.0 V silver oxid battery. Does someone have experience if it would work and indicate the correct exposure?

thanks,

 

[erikhaugsby]

(Disclosure - I have no personal experience with either the 35SE or replacement batteries for the PX27.)

There's a thread on the Rollei Club Forums that talks about replacement batteries. The PX27 mercury battery was 5.6v. The PX27A silver-oxide battery is listed as 6v, but tests show it delivers 6.2v - and "pooped out after a roll or two, possibly due to poor mAh capacity."

I've got a Rollei 35S (which eats PX625 mercury batteries) and am looking at getting an adapter from CRIS. They also make one for the PX27, called the V27px. It lets you use 386 silver-oxide batteries without modification.

 

[Griffin]

Copied from my reply on a flickr discussion:


The alkaline PX27a batteries work perfectly on the SE, you just need to adjust your ISO down one notch. So you can shoot 800 speed film, but set the dial to 400.

Link to discussion:
http://www.flickr.com/groups/rollei35/discuss/72157623982634279/

I have shot about four rolls using this method. Exposure seems spot on.

 

[jschrader]

thanks for the suggestions.
I will probably try to get a PX27A and compare it to another lightmeter before using.

Hope it is not empty that soon.

Having a handheld light-meter is somehow not so attractive if one uses the Rollei for the small size.

 

[Highway 61]

On internet I found that there is a similar sized 6.0 V silver oxid battery. Does someone have experience if it would work and indicate the correct exposure?

thanks,

The 35SE meter circuitry allows the use of a 5V to 6V voltage source with perfectly correct metering so you can use the 6.0V silver battery with no problem.

You can also use four small 1.5V 386PX batteries stuck together with a piece of adhesive tape. No need to buy any "adapter" which consists of an empty plastic shell.

Whatever is less expensive.

I have even used three 1.55V 76PX batteries and a small ball of aluminum paper to fill the empty space in the battery compartment and the meter worked perfectly even with a 4.65V voltage source... 🙂

 

[erikhaugsby]

The alkaline PX27a batteries work perfectly on the SE, you just need to adjust your ISO down one notch. So you can shoot 800 speed film, but set the dial to 400.

I've used alkaline 625A batteries in my 35S, and although they start out great there are some sacrifices - notably their power discharge isn't consistent. It starts out at 100% but quickly drops off and has an increasingly (but not linearly) lower voltage as the battery ages. Check out the graph on chart 3 of this PDF from Butkus.org for a visual depiction of the discharge curves of different types of batteries.

What this means in practical terms is your meter will tell you to underexpose your film. At the beginning of the battery life exposures will be consistent, but using the battery without changing any settings (exposure compensation or film speed) will increasingly underexpose your film. There isn't an easy way to tell the exact voltage that the battery is putting out at any given point in time, so there isn't an easy way to tell exactly how much compensation should be applied. 😡

Silver-oxide batteries and Zinc-air batteries, like mercury batteries, both output consistent voltages throughout their life before dying quickly and dramatically. The problem for us is that silver-oxide batteries put out more voltage than mercury batteries, and zinc-air batteries aren't easy to find in the sizes used by most cameras.

 

[Highway 61]

I've used alkaline 625A batteries in my 35S, and (...)

Here we are talking about the 35SE.

The 35S meter needs 1.35V and is voltage-sensitive. It will not work properly with 1.5V batteries indeed, and those zinc-air batteries are a mess I agree. So for the 35S the only viable solution is to either tune-up the two hi-lo meter potentiometers so that the meter works well with a 1.5V battery, or to use an MR-9 adapter which drops a 76PX 1.5V battery voltage to 1.35V and fits in the original 625PX battery compartment.

The 35SE has totally different meter and circuitry than the 35S.

 

[erikhaugsby]

The 35SE has totally different meter and circuitry than the 35S.

That's what I get for getting into a conversation about a camera I haven't used, and assuming the camera has circuitry similar to one I have used. 😱

 

[jschrader]

thanks once more,

thanks once more,

the picture is getting clearer. I think (from my understanding of physics) that besides the voltage a constant inner resistivity in the battery (meaning how much current does it produce on a given load) is also critical.

I will give it a try and see.

I gave up my Nikkormat FTn for a FE because I didn't buy enough batteries before they disappeared from the market. And from You suggestions, highway61, I assume the problem shoud be less on the Rollei. It would also be more difficult to replace ;-)