You’ll need a battery, in order to put your Minox camera or its meter to work. You’ll need batteries for the following:
Minox C – PX27 / S27PX / Exell 6V / Minox adapter 4 cells
Minox EC – PX27 / S27PX / Exell 6V / Minox adapter 4 cells
Minox LX – PX27 / S27PX / Exell 6V / Minox adapter 4 cells
Minox CLX – PX27 / S27PX / Exell 6V / Minox adapter 4 cells
Minox TLX – PX27 / S27PX / Exell 6V / Minox adapter 4 cells
Minox battery adapter (takes 4 x of 1.5V)
Minox BL – PX625 (replaced by Weincell MRB 675 zinc-air)
(the battery only activates the CdS meter. The camera can be used without it, similar to a IIIs).
Minox AG-1 (bulb) flash gun – Eveready 504, 15V
Minox C4 (cube) – Eveready 504, 15V
One should note that the Minox camera circuitry was not designed to take 6V. The meter especially was designed to take nominal 5.6V batteries, since the mercury 5.6V batteries were readily available on the market during the period of 50’s to 80’s. As this is not the case anymore, replacing the mercury ones with fresh 5.6V from Varta, Duracell and oher brands will be all right. The problems start when the 6V are inducing a higher voltage in the meter. I have yet to see a 6V dedicated battery which will properly fit a Minox camera. What a lot of people do is getting 4 x 1,5V in a small tubing and there you go: a 6V battery. Not good.
However, if you use a Minox adapter instead of a 5.6V battery seem to be all right; the adapter has a thicker metal bottom, which apparently diminishes the voltage from 6V to 5.6V or thereabouts, thus making it suitable for Minox meter proper activation.
I do not like to use 4 x 1.5V cells into my adapters. The discharge curve is sloped, thus your meter may behave erratical after the battery has been driven to a small charge left in it. I prefer those batteries which have an abrupt discharge curve, so I’ll know really fast battery is exhausted.
Anyways, if I must use a battery adapter, I always load the tube with 1 x CR1/3N plus 1 x LR44 plus 1 x AG13. All silver oxide.
And for your camera sake, do youself a favor and replace the mattery at least once a year, even if you did not used the camera. AND do not keep batteries inside the camera when not in use.