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Voltage close to the original: Operating voltage of 1.25–1.30 V instead of the excessively high 1.5 V of an alkaline battery — accurate metering with CdS light meters, with no incorrect exposures on negative film.
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Direct replacement instead of an adapter ring: The V80H fits directly into your camera’s battery compartment without an MR-9 adapter or a diode for voltage adjustment.
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Rechargeable instead of disposable: A V80H battery rechargeable via USB-C replaces expensive zinc-air cells that dry out after a few weeks.
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Ready-made charger instead of DIY work: Custom PCB, USB-C port, housing with spring contacts. Plug it in, charge it, done.
Safety instructions
Please charge the V80H battery exclusively in the charger provided for this purpose. Charging indicator: The blue LED indicates that the USB-C cable is connected. There is no full-battery indicator — a complete charging cycle takes approximately 8 hours.
Compatibility
Replacement for the 1.35 V mercury battery PX625 (IEC designation MR9). Suitable for 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 (Demi, Demi S, EE17, Dial 35 II) [...]
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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 whether the battery fits your camera?
Here is a complete list of all cameras compatible with the PX625 battery type.
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
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Pro Pack + battery compartment tool: 1x USB-C charger + 2x V80H batteries + 1x coin tool for opening the battery compartment
Technical details
- 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 — sufficient for weeks with the microampere consumption of a CdS meter
- Charging method: Gentle trickle charging (C/7) via USB-C
- Charging time: approximately 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 PX625 mercury battery (IEC MR9) and is charged via USB-C. With an operating voltage of 1.25–1.30 V, it keeps your CdS light meter working correctly — without an adapter ring or diode, directly in the battery compartment. It fits, among others, the Rollei 35, Leica CL, Olympus OM-1, Canon F-1 and Minolta SR-T.
The traditional workaround for the 1.35 V PX625 mercury battery (IEC MR9) was an adapter with a diode to lower the voltage — necessary because classic analogue cameras such as the Rollei 35, Leica CL, Olympus OM-1, Canon F-1 and Minolta SRT were designed specifically for this battery. Since production was banned, there has been no replacement solution that combines the correct voltage, dimensions and service life. The most common alternative (1.5 V alkaline) provides too high a voltage, which leads to incorrect exposures, particularly with CdS light meters.
The Varta V80H solves this problem with an operating voltage of 1.25–1.30 V, which is significantly closer to the original. It is not an ordinary NiMH battery: The V80H comes from Varta’s industrial “Robust” series (designed for server RTCs and medical technology) and uses LSD-NiMH technology (low self-discharge) — its self-discharge rate is comparable to that of the Eneloop series.
The idea of using a V80H as a PX625 replacement comes from Troeszter.net. Building on this idea, we developed a standalone product: a custom PCB, USB-C instead of a laboratory power supply, and a housing with spring contacts.
In cameras such as the Rollei 35 or Leica CL, the battery compartment is located in the film chamber — every battery change means removing the film. With the Pro Pack (2x V80H), you can simply change the battery every time you change the film.
Frequently asked questions
“1.2 V is too low — the original was 1.35 V”
The nominal voltage shown on the datasheet is the average over the entire discharge cycle. Our measurements in a Rollei 35 show that a fully charged V80H delivers 1.30–1.32 V. After two weeks, it still delivers 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 isn’t enough”
A CdS light meter consumes microamperes. At this consumption level, the V80H’s stable voltage plateau lasts not hours but weeks. 80 mAh is little for AA batteries — but sufficient for a camera button cell.
“But NiMH batteries discharge by themselves”
Standard NiMH batteries lose 10–20% of their charge in the first few days. The V80H is not a standard NiMH battery. As a low-self-discharge cell from Varta’s “Robust” series, it retains approximately 80% of its capacity after one year at room temperature — comparable to the Eneloop series.
Practical notes
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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 temperatures: Below 5 degrees Celsius, NiMH batteries become unreliable. For winter photography in freezing conditions, a zinc-air cell or alkaline battery + ISO compensation is the 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 switch off when power consumption is low. The charger requires a USB source that does not switch off with small loads (power adapter or laptop port).
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Leica M5: The M5’s screw cap is tighter than those of other PX625 cameras, so the V80H may get stuck there. If you cannot insert it properly into the compartment, use a Type-675 zinc-air cell for the M5 — it is smaller and fits directly into the M5 without an adapter.
Detailed comparison of all PX625 alternatives (alkaline, zinc-air, Schottky adapter, V80H and DIY solutions), including measurement data, practical tests and community feedback: View the complete PX625 guide.
