Battery for Spotmatic SP500

Many apologies if this has been asked before, I'm sure it has but I can't find anything recent.

Does anyone know what currently available battery, if any, will work in the Pentax SP500 camera? Thank you.

Hi Dave

You can get away with Rayovac Hearing Aid batteries, see link below:

link

They just about fit and work the meter with no problems. Hope this helps.

Regards
David

The Spotmatics were built to use a mercury battery (PX400/V400PX/RM400)of 1.35v, as were many other cameras of the time. Unfortunately the mercury batteries were discontinued in the 1970's but due to the forethought and good design of Pentax cameras, a bridge circuit on the battery, they are not sensitive to different battery voltages!
As long as it fits ok in the battery chamber, an SR44 (silver)or LR44(alkaline) 1.5v battery will work the meter fine. These are the same as the ones used on the K, M, P and most of the A series cameras. They are a different shape but usually will fit ok but may want a bit of careful packing with a bit of paper or thin card, to keep them central in the battery chamber and in contact with the battery contacts.
There is also a battery replacement for the old PX400 battery called a WEIN Cell but they are expensive and don't last well, whereas the LR44 are cheap and easy to get hold of.

All the best, Bob

To make the LR44's work in a Spotmatic, you have to remove the plastic round piece in the battery compartment, otherwise they do not fit. The plastic can be brittle and can break when removing it. This is why I use the Rayovac Hearing Aid batteries as the battery compartment will take them with no modifications.

Regards
David

After too much fiddling around, I went for a replacement battery cover that takes the hearing aid batteries which are common and cheap as chips. The cover is pricey as it contains (unnecessary) electronics to adjust the voltage, but in the longer term it will be cheaper than Wein cells and easier to use. It also can be moved around my various varieties of Spottie.

https://www.ebay.co.uk/itm/1-35V-PX400-MR-42-RM400-H-B-MRB400-Adapter-Battery-Fo...

These too, as they come with a spacer to help with the fit

Note though that the Spotmatic F used a different battery, a PX625. IIRC this is also the battery used in the square clip on meter for the SV etc series.


This was my choice, especially as one camera had a missing battery cover. The original covers cost more than a full camera. Long version, the battery cover was welded to the baseplate by a leaked battery, I was able to get a replacement baseplate but without the cover.

Hello everyone. Thanks very much for your help. Much appreciated.

I didn't know such things existed. Can you tell me where you got it?

Edit: is it this? https://www.smallbattery.company.org.uk/sbc_h-b_adapter.htm

Yup, that's the one. Cheaper if you happen to be in the US from the manufacturers (CRIS) as the price in US$ is the same numbers as the Small Battery company charge in UK£.