PX27 Battery Adapter Set for Minox 35 GT, EL, GL

• Stable voltage until just before discharge: SR44 silver-oxide cells deliver 4 x 1.55V = 6.2V with a flat discharge curve, almost identical to the original PX27 mercury battery. No gradual drift like with alkaline (LR44).
• Original dimensions without DIY modifications: The adapter brings four SR44 cells to exactly 12.7 x 20.5 mm. The battery compartment cover closes properly, with stable contact and no adhesive tape.
• Ready to use immediately: Four compatible SR44 cells are included with every variant. Insert them, screw the cover closed, and keep shooting.
• Affordable standard cells instead of expensive disposable stacks: SR44 (type 357) is a standard button cell, available in a 10-pack for under EUR 5. Replacing the batteries costs around EUR 2. The adapter itself is a one-time purchase.

Compatibility

Suitable for various cameras, including:

• Minox: 35 EL, 35 GL, 35 GT, 35 PE, 35 PL, C, LX [...]
• Rollei: 35 LED, 35SE, 35TE, A110, E110
• Agfa: Optima 335, Optima Sensor Flash
• Hanimex: VEF Zoom

Not suitable for Minox 35 ML, MB, and M.D.C. (these require a PX28 adapter).

Also not suitable for the later Minox 35 models from 1988 onward: GT-E, GT-E II, GS-E, GT-S, GT-X, and Gold Button Edition. Their built-in battery holder takes two CR 1/3N cells with a diameter of 11.6 mm. At 12.7 mm, the PX27 sleeve is too thick for them. The correct battery: CR 1/3N lithium cell.

Not sure whether the adapter fits your camera? Complete list of all cameras compatible with the PX27 battery type.

Scope of delivery

• Standard: 1x PX27 adapter + 4x SR44 batteries
• Set: 1x PX27 adapter + 4x SR44 batteries + 2x ISO plates (replacement)
• Complete: 1x PX27 adapter + 4x SR44 batteries + 2x ISO plates + 1x 30.5mm filter adapter

Technical details

• Adapter material: engineering plastic
• Color: Black
• Dimensions: 12.7 mm x 20.5 mm (identical to PX27)
• Battery system: 4x SR44 silver oxide (1.55V per cell, 6.2V total)
• Replacement for: PX27 / V27PX / 4SR43 / EPX27

Description

The Minox 35 GT, GL, EL, and PL originally required the PX27 mercury battery with 5.6V. Since the mercury ban, there has been no identical replacement. This adapter holds four SR44 silver-oxide cells and brings the stack to the exact original PX27 dimensions of 12.7 mm x 20.5 mm: 6.2V with a flat discharge curve, securely seated cells, and a battery compartment cover that closes without force.

The typical workaround of wrapping four button cells in adhesive tape and hoping the stack fits is unreliable and causes contact problems. Besides the Minox 35 series, the adapter also fits, among others, the Rollei 35 LED and A110.

Practical tips

• Insertion: Insert the batteries into the adapter, place the adapter in the battery compartment, and screw the cover closed. The adapter ensures the correct polarity.
• Storage protection: Place the included insulation disc between the adapter and the battery compartment contact when the camera will not be used for an extended period. This prevents self-discharge.
• First roll: Use ISO 400 negative film for the first roll after replacing the batteries. Its wide exposure latitude forgives slight deviations while you get a feel for the exposure.
• Reordering: SR44 batteries (also known as 357, SB-B9, or SR44W) are available everywhere. You are not tied to a specialist supplier.

Alternative names for this battery type: PX27, V27PX, 4SR43, S27PX, PX27S, RPX27S, PX27A, 4LR43, A27PX, 4AG12, U27PX, V7150, Varta 7150, L7150, EPX27, KX27, RPX27, H-4N, MER27, HS3C, 1413MP, 4NR43, VPX27

Want to learn more about battery alternatives for analog cameras? In our FAQ article on batteries and adapters, we explain all options in detail, including voltage comparisons and recommendations by camera type.

Frequently asked questions

“Do 4x SR44 batteries actually fit in the battery compartment?”

Without an adapter: barely, if at all. Four SR44 batteries measure 21.6 mm in height. The PX27 compartment is designed for 20.5 mm. A difference of 1.1 mm is enough to prevent the cover from closing. Four LR43 batteries, on the other hand, measure 16.8 mm and are too short, so they rattle. The adapter compensates for the height difference and provides the correct outer diameter. In analog photography forums, this fit problem is a recurring topic.

“6.2V instead of 5.6V—is the exposure still correct?”

Practical tests and community experience show that the Minox 35 series operates at 6.0–6.2V without relevant exposure deviations in normal daylight. In low-light conditions (dusk, indoors), a slight tendency toward underexposure may occur. If you want to play it safe, reduce the ISO setting by one stop. Negative film easily absorbs this minimal difference.

“Why SR44 and not alkaline (LR44)?”

The original PX27 was a mercury battery with 5.6V and an extremely flat discharge curve. The Minox 35’s automatic exposure system has no internal voltage regulator. It responds directly to the battery voltage. SR44 silver-oxide cells deliver 4 x 1.55V = 6.2V with a similarly flat curve: the voltage remains stable until the cell drops sharply at the end of its service life.

LR44 alkaline cells start at 4 x 1.5V = 6.0V and then drop continuously. Exposure is correct at first, but not after a few weeks. In analog photography forums, Minox owners regularly report deviations of around one stop when using LR44 batteries, without realizing that the battery is the cause.

“Wouldn’t 2x CR1/3N lithium batteries be enough?”

2x CR1/3N batteries provide 6.0V with a flat discharge curve, which looks like a good alternative on paper. In practice, photographers report CR1/3N cells that already deliver insufficient voltage from the factory (2.7V instead of 3.0V). This is especially common with inexpensive suppliers and marketplace counterfeits. SR44 is too inexpensive as a standard watch battery to be attractive to counterfeiters. This risk is eliminated. The situation is different with later Minox 35 models from the GT-E (1988) onward: there, 2x CR 1/3N is the battery type specified by the manufacturer, and this adapter does not fit their battery holder.

“Why not simply buy a ready-made PX27 replacement battery?”

GoldenPower and similar PX27 replacement batteries contain 4x LR43 cells in a plastic housing. They use alkaline cells with a declining discharge curve and only around half the capacity of an SR44. Cost: EUR 8–15 per battery, despite unstable voltage and more frequent replacement. Ready-made 4SR44 or 4LR44 stacks offer no advantage either: EUR 5–7 per stack instead of around EUR 2 for four individual SR44 cells, and they are only available from specialist retailers. For the same price, you get our adapter plus 10 SR44 silver-oxide cells, each with a flat discharge curve and twice the capacity.