PX625 rechargeable battery with USB-C charger

• Voltage close to original: Operating voltage 1.25–1.30 V instead of the too high 1.5 V of an alkaline — correct measurement with CdS light meters, no misexposures on negative film.
• Direct replacement instead of adapter ring: The V80H fits directly into your camera’s battery compartment without an MR-9 adapter and without a diode for voltage adjustment.
• Rechargeable instead of disposable cell: A USB-C rechargeable V80H battery replaces expensive zinc-air cells that dry out after weeks.
• Ready-made charging station instead of DIY: Own PCB board, USB-C connection, housing with spring contacts. Plug in, charge, done.

Safety instructions

Please charge the V80H battery only in the designated charger. Charging indicator: The blue LED shows that the USB-C cable is connected. There is no full battery indicator — a full charge takes about 8 hours.

Compatibility

Replacement for the 1.35 V mercury battery PX625 (IEC designation MR9). Suitable for various cameras, 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) [...]
• Nikon: F series (F, F Photomic, FTN), Nikkormat / Nikomat series (FT, FTN) [...]
• Minolta: SR-T series (100-303, MC, SC, Super), SR series (1, 7, 100-505), Hi-Matic series (7, 7S, 9, 11) [...]
• Olympus: OM-1 series (OM-1, MD, N), 35 series (RC, RD, SP, DC), Pen series (F, FT, D2, EED) [...]
• Pentax: K series (K2, KM, KX), Spotmatic F, H series (H1a, H3v) [...]
• Rollei: 35 series (35, 35S, 35T, Classic), SL35 series (SL35, SL35M, SL350), XF35 / A26 [...]

Not sure if the battery fits your camera?
Here is a complete list of all cameras compatible with the PX625 battery type.

Scope of delivery

• Standard: 1x USB-C charger + 1x V80H battery (PX625-compatible)
• Pro Pack: 1x USB-C charger + 2x V80H batteries

Technical details

• Battery: Varta V80H (Low Self-Discharge NiMH, 80 mAh)
• Nominal voltage: 1.2 V (according to manufacturer)
• Operating voltage (plateau): 1.25 – 1.30 V
• Capacity: 80 mAh — sufficient for weeks at microampere consumption of a CdS meter
• Charging method: gentle slow charging (C/7) via USB-C
• Charging time: approx. 8 hours (overnight charging recommended)
• Charger material: technical plastic
• Connection: USB-C (PD compatible)

Description

In short: The Varta V80H is a rechargeable replacement for the discontinued 1.35 V mercury battery PX625 (IEC MR9) and is charged via USB-C. With an operating voltage of 1.25–1.30 V, it keeps your CdS light meter accurate — without adapter ring or diode, directly in the battery compartment. Fits, among others, Rollei 35, Leica CL, Olympus OM-1, Canon F-1, and Minolta SR-T.

The classic emergency solution for the 1.35 V mercury battery PX625 (IEC MR9) was long an adapter with a diode that lowers the voltage — necessary because analog camera classics like Rollei 35, Leica CL, Olympus OM-1, Canon F-1, or Minolta SRT were designed specifically for this battery. Since the production ban, there has been no replacement that covers voltage, form factor, and durability at the same time. The most common alternative (1.5 V alkaline) delivers too high a voltage, which especially leads to misexposures with CdS light meters.

The Varta V80H solves this problem with an operating voltage of 1.25–1.30 V, much closer to the original. It is not an ordinary NiMH battery: The V80H comes from Varta’s industrial “Robust” series (built for server RTC and medical technology) and uses LSD-NiMH technology (Low Self-Discharge) — self-discharge is comparable to the Eneloop series.

The idea to use a V80H as a PX625 replacement comes from Troeszter.net. Building on that, we developed an independent product: own PCB board, USB-C instead of lab power supply, housing with spring contacts.

In cameras like the Rollei 35 or Leica CL, the battery compartment is inside the film chamber — every battery change means: remove the film. With the Pro Pack (2x V80H), you can easily change the battery with every film change.

Frequently asked questions

“1.2 V is too low — the original had 1.35 V”

The nominal voltage on the datasheet is the average over the entire discharge cycle. Our measurements in a Rollei 35 show: freshly charged, the V80H delivers 1.30–1.32 V. After two weeks, still 1.27–1.28 V. The deviation of 0.05–0.08 V is within the tolerance range for negative film.

“Only 80 mAh capacity — that’s not enough”

A CdS light meter consumes microamperes. At this current consumption, the stable voltage plateau of the V80H lasts not hours but weeks. 80 mAh is little for AA batteries — for a camera button cell it is sufficient.

“NiMH discharges by itself”

Standard NiMH loses 10–20% charge in the first days. The V80H is not standard NiMH. As an LSD cell (Low Self-Discharge) from Varta’s “Robust” series, it retains about 80% capacity after one year at room temperature — comparable to the Eneloop series.

Practical notes

• Battery check: Many cameras (OM-1, Minolta SRT) have a battery check calibrated to 1.35 V. The V80H shows “empty” there — although the light meter works perfectly. This is normal.
• Cold: Below 5 degrees Celsius, NiMH becomes unreliable. For winter shots in frost, a zinc-air cell or alkaline + ISO correction is the better choice.
• After charging: Let the V80H rest for 1–2 hours after charging before putting it in the camera. The resting voltage stabilizes during this time.
• Power bank: Some power banks switch off at low current consumption. The charger requires a USB source that does not switch off small loads (power supply or laptop port).

Detailed comparison of all PX625 alternatives (alkaline, zinc-air, Schottky adapter, V80H, and DIY solutions) with measurement data, practical tests, and community feedback: To the complete PX625 guide.