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OM1 Battery Problem


Well-Known Member
I don't know if anyone is out there as there are no posts here for awhile. I have recently acquired a couple of nice OM-1's and am wondering what people recommend concerning batteries since as far as I can see the correct mercury 1.35v battery is not only no longer available, but is also illegal.

As far as I can see there seem to be three options: 1. Use a zinc-air cell with an O-ring (and change batteries often). 2. Buy an MR9 adapter from CRIS and use 1.5v silver oxides. 3.Have the camera modified by someone such as Camtech so that it can use 1.5v silver oxides.

I am currently using the first one and it works ok. I would prefer a better solution. I guess I am wondering why no one manufacturs a more acceptable alternative for the original battery.
I have the same problem and I have not yet figured out the simple way to use alternative battery. So I just use the camera without battery.
For accurate meter readings using a 1.35V button cell in the OM-1 there is only one option and that is the Wein Cell MRB625. In the UK I get it from the small battery company. Although expensive I would suggest this and it will last for 6 months. I have measured the meter reading against a lightmeter and it is spot on. If the camera has not been adapted to take a 1.5V batterry I would not put one in and adjust shots respectively. The light meter is made from cadmium sulphide and a higher voltage may lead to degradation of the material over time.
I think that may be the long-range solution if I am going to keep my cameras. They need new foam anyway, so ultimately I will probably have the conversion done when I send them in to be overhauled. Weincells are the closest thing to the original that is available, but they are very expensive (the last one I got was $8).
> My local camera shop switched my battery for me. I noticed my light meter was 3 stops too high! I did some research, and found out the voltage of the new cell was too high. I also gound out that a # 675 battery for hearing aids is the right voltage. You just need to place a rubber O-ring around it to make it fit in your battery compartment. I did this and my meter is dead on now. I got 10 of these batteries as they where only $6.00. They do not last as long as the mercury cells, but it was a cheap fix.

> I understand you can prolong the life of the hearing aid batteries by sealing up all the little holes save one, using varnish or something similar. They run on exposure to the air and this reduces their output. Since camera meters don't need as much juice as hearing aids everything still works just as well.
"I guess I am wondering why no one manufacturs a more acceptable alternative for the original battery."

Probably because the only practical way of generating 1.35V is by using a mercury battery. As this is now illegal (as you point out) this leaves no alternative, acceptable or otherwise.

I myself use an adapter which is probably similar to the CRIS option - this works very well for me as silver batteries are reliable and easily obtained.

A conversion should also give good results.
> an overhaul on OM-1 or 1N, I convert it for use with silver oxide > 1.55v batteries (MS76, KS76, 357, 303, SR44W, G13). I install a > nylon ring in teh battery box and a diode in the meter circuit. > Silver oxide batteries won't last nearly as long as mercury, but the > resultiung conversion is very accurate. John Hermanson, www.zuiko.com]
I would just like to add that John is a top-notch job and does great work. He recently rebuilt an Olympus 35-SP (rangefinder, see http://www.flickr.com/photos/97373293@N00/64641523/, the SP is the one on the left), and put new leather on for me. The battery conversion was a very neat, tidy job. And the meter is spot on; it exactly matches another SP I have that was recently CLA'd elsewhere and is running on a mercury PX625 battery. Now I have two wonderful SPs; I need left and right holsters, I suppose to challenge Leica shooters to a shootout at the OK corral!