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—no adapter ring or diode needed, fitting directly into the battery compartment. Compatible with cameras such as Rollei 35, Leica CL, Olympus OM-1, Canon F-1, and Minolta SR-T.
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Voltage close to the original: Operating voltage 1.25–1.30 V instead of the too high 1.5 V of an alkaline battery—correct readings on CdS light meters, no exposure errors on negative film.
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Direct replacement instead of adapter ring: The V80H fits directly into your camera’s battery compartment without an MR-9 adapter or diode for voltage adjustment.
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Rechargeable instead of disposable: A USB-C rechargeable V80H battery replaces expensive zinc-air cells that dry out after weeks.
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Ready-to-use charging station instead of DIY: Own PCB board, USB-C port, 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 the USB-C cable is connected. There is no full-charge indicator—the full charging process takes about 8 hours.
Compatibility
Replacement for the 1.35 V mercury battery PX625 (IEC designation MR9). Fits various cameras, including:
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Canon: Canonet series (QL17, QL19, 28, G-III), F series (F-1, FT, FTb, FX), Demi / Dial series [...]
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Nikon: F series (F, F Photomic, FTN), Nikkormat / Nikomat series (FT, FTN) [...]
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Minolta: SR-T series (100-303, MC, SC, Super), SR series (1, 7, 100-505), Hi-Matic series (7, 7S, 9, 11) [...]
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Olympus: OM-1 series (OM-1, MD, N), 35 series (RC, RD, SP, DC), Pen series (F, FT, D2, EED) [...]
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Pentax: K series (K2, KM, KX), Spotmatic F, H series (H1a, H3v) [...]
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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.
Package Contents
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Standard: 1x USB-C charger + 1x V80H battery (PX625-compatible)
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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—enough 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
The classic emergency solution for the 1.35 V mercury battery PX625 (IEC MR9) was long an adapter with a diode to lower 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 perfect replacement solution. The most common alternative (1.5 V alkaline) delivers too high a voltage, which especially causes exposure errors 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 (made for server RTC and medical technology) and uses LSD-NiMH technology (Low Self-Discharge)—its self-discharge is comparable to the Eneloop series.
The idea to use a V80H as a PX625 replacement comes from Troeszter.net. Building on this, we developed an independent product: our own PCB board, USB-C instead of a lab power supply, housing with spring contacts.
In cameras like the Rollei 35 or Leica CL, the battery compartment is inside the film chamber—each battery change means removing the film. With the Pro Pack (2x V80H), you can easily swap the battery at every film change.
Common Concerns—and Our Answers
“1.2 V is too low—the original was 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, the stable voltage plateau of the V80H lasts not hours but weeks. 80 mAh is low for AA batteries—but sufficient for a camera button cell.
“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 Tips
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Battery check: Many cameras (OM-1, Minolta SRT) have a battery check calibrated for 1.35 V. The V80H will show “empty” there—even though the light meter works perfectly. This is normal.
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Cold: Below 5 degrees Celsius, NiMH becomes unreliable. For winter shooting in frost, a zinc-air cell or alkaline + ISO correction is a better choice.
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After charging: Let the V80H rest for 1–2 hours after charging before inserting it into the camera. The resting voltage stabilizes during this time.
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Power bank: Some power banks shut off at low current draw. 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: Full PX625 Guide.
