PX625 rechargeable battery with USB-C charger

Replacement for the 1,35 V PX625 mercury battery (IEC designation MR9). Suitable for various cameras and light meters, including:

• Canon: Canonet series (QL17, QL19, 28, G-III), F series (F-1, FT, FTb, FX), Demi / Dial series (Demi, Demi S, EE17, Dial 35 II), Overview of Canon models using PX625
• Nikon: F series (F, F Photomic, FTN), Nikkormat / Nikomat series (FT, FTN), Overview of Nikon models using PX625
• Minolta: SR-T series (SR-T 100, 100X, 101, 102, 201, 202, 303, 303b, MC, SC, Super), SR series (1, 7, 100-505), Hi-Matic series (7, 7S, 9, 11), Overview of Minolta models using PX625
• Olympus: OM-1 series (OM-1, MD, N), 35 series (RC, RD, SP, DC), Pen series (F, FT, D2, EED), Overview of Olympus models using PX625
• Pentax: K series (K2, KM, KX), Spotmatic F, H series (H1a, H3v), Overview of Pentax models using PX625
• Rollei: 35 series (35, 35S, 35T, Classic; not the 35 SE/TE, which need a PX27), SL35 series (SL35, SL35M, SL350), XF35 / A26, Overview of Rollei models using PX625
• Leica: CL, M5 with limitations (see below); not for the Leicaflex SL
• Gossen: Luna-Pro / Lunasix series (Luna-Pro, Luna-Pro S, Luna-Six 3, Lunasix 3S), Sixtomat Electronic, Sixtar / Sixtar 2, Super Pilot / Super Pilot SBC, Overview of Gossen models using PX625
• Sekonic: L-98 Micro-Leader, L-218 (Apex, Autorange), L-228 Zoom-Meter, L-248 Multi-Lumi, Marine Meter series (L-164, L-184C, L-1484), Overview of Sekonic models using PX625

Light meters often need two cells, cameras usually just one: the Gossen Luna-Pro, Luna-Pro S, Luna-Six 3, Lunasix 3S and Sixtomat Electronic run on two. For these, there are versions with 2 rechargeable batteries. Don't confuse them: the Luna-Pro F and Luna-Pro SBC run on a 9 V block battery, so this cell won't fit there.

Leica M5: The screw cap fits more tightly than on other PX625 cameras, so the V80H can get stuck there. In that case, use a type 675 zinc-air cell, which fits directly into the M5 without an adapter.

Not suitable for the Leicaflex SL: its battery compartment is too narrow. A tester tried the V80H in their SL for us, and the screw cap does not engage.

Not sure if the battery fits your camera?
Here is a complete list of all cameras and light meters that take the PX625 battery type.

On the Rollei 35 or Leica CL, the battery compartment sits in the film chamber. With two rechargeable batteries, you swap the battery along with every film change.

• Rechargeable battery: Varta V80H, Low Self-Discharge NiMH, 80 mAh
• Nominal voltage: 1,2 V (according to the manufacturer)
• Operating voltage (plateau): 1.25–1.30 V
• Capacity: 80 mAh, enough for weeks at the microampere draw of a CdS meter
• Charging method: gentle slow charging (C/7) via USB-C
• Charging time: approx. 9 hours (charging overnight recommended)
• Charger material: engineering plastic
• Connection: USB-C, fixed 5 V without negotiation via fast-charging protocol (PD)
• SKU: 1371

Since the production ban on the PX625 mercury battery (IEC MR9), there has been no replacement that covers voltage, form factor and longevity at the same time. The Varta V80H is an industrial rechargeable battery with low self-discharge and fits, among others, the Rollei 35, Leica CL, Olympus OM-1, Canon F-1 and Minolta SR-T. The idea of using it as a PX625 replacement comes from Troeszter.net; based on it, we developed our own charger with our own circuit board, USB-C and spring contacts. You can find measurement data and the comparison of all PX625 alternatives in the PX625 guide.

“1,2 V is too little. The original had 1,35 V”

1.2 V is the nominal voltage of every NiMH cell. Under the tiny load of the light meter, Troeszter.net measured 1.30–1.32 V freshly charged in the Rollei 35T and 35S, and 1.25–1.27 V after four weeks. The deviation goes in the direction of overexposure, and negative film handles that easily.

“Does my light meter really measure correctly with it?”

Troeszter.net checked this at a standardized light table against the old mercury cell, and a customer on his Voigtländer VF 135 against a Sekonic handheld light meter: the same readings. You can check it yourself with a gray card, metering once with the camera and once with a handheld light meter or app. If both agree within a third of a stop, it's fine.

“Isn't that expensive compared to zinc-air cells?”

In purchase price, yes: for a single camera, zinc-air is the cheapest option. Our PX625 adapter with six cells costs less than half as much as the rechargeable battery with charger. An activated zinc-air cell usually lasts 2 to 3 months in the camera, and only a few weeks in heat or in very dry or humid air. With three regularly used cameras, the rechargeable battery breaks even after three years; you’ll find the calculation in the PX625 guide.

“Only 80 mAh capacity. That's not enough”

It is enough for the microamp draw of a CdS light meter: depending on the camera, you recharge every few weeks to two months.

“But NiMH discharges on its own”

Standard NiMH loses 10–20% of its charge in the first few days, while the V80H still retains approx. 80% of its capacity after one year at room temperature.

“Can I charge the V80H in my regular battery charger?”

No. Varta specifies a charging current of 7 to 14 mA (datasheet). An AA or AAA charger delivers many times that, even with clips or a cork, and the cell gets hot and can leak. Our charger charges at about 11 mA.

“Can't I just use an alkaline and compensate with the ISO dial?”

An alkaline drops from just under 1.6 V to about 1.2 V, the correction that is right today will be wrong in four weeks, and too much voltage means underexposure. The V80H holds 1.25–1.30 V, and the remaining deviation is less than a third of a stop towards overexposure.

“The light meter isn't responding. What should I do?”

Check the polarity, clean the contacts in the battery compartment and freshly charge the cell. If it still doesn't work, the fault may lie in the camera. Write to us and we'll help you narrow it down.

• First charge: Fresh out of the box, the V80H is only partially charged. Charge it fully once overnight and let it rest for 1–2 hours before it goes into the camera.
• Battery check: The battery check button on the OM-1 or Minolta SRT is calibrated to 1.35 V and shows “empty” with the V80H, even though the light meter is metering correctly. This is normal.
• No off switch: On the Rollei 35, the light meter draws current as soon as light falls on the metering cell, even with the lens cap on. Keep the camera in a bag or drawer.

Below 5 degrees Celsius, NiMH becomes unreliable. If you won't use the camera for months, remove the cell, store it partially charged and recharge it every 6–12 months. We accept no liability for defects in the camera itself; in that case, a service by a camera technician will help.