Leaf AFi-II 7 Replacement Battery 7.4V 5500mAh Li-ion

Leaf AFi-II 7 / Aptus Series — 7.4V Li-ion Replacement Battery

This is a 7.4V, 5500mAh (40.7Wh) Li-ion replacement battery for the Leaf AFi-II 7 and Aptus 22, 65, and 75 medium format digital camera backs. It slots into the same battery bay as the original cell and runs the same voltage rail. Use it when the original pack no longer holds a charge or when back-to-back shoots demand a spare.

• AFi and Aptus platform fit: These Leaf camera backs share a common battery form factor and 7.4V power architecture. The same cell feeds the image sensor, digital back processor, and storage interface across the AFi-II 7, Aptus 22, Aptus 65, and Aptus 75.
• Bench tested on actual hardware: We cycled this cell through a full charge-discharge sequence and confirmed the BMS holds the 7.4V nominal rail without voltage sag under sustained sensor and processor load. Capacity measured within 3% of the rated 5500mAh.
• First-use charge cycle on the Leaf back: Before heavy studio use, run one complete charge cycle through the camera body or OEM charger. Leaf's battery-remaining display maps to a known discharge curve — charging from inside the body lets the BMS calibrate the new cell's curve for accurate shot-count tracking.

Dead battery indicator on the AFi-II 7 with a partially charged replacement cell

The Leaf AFi-II 7 uses voltage-threshold mapping to estimate remaining charge. A new replacement cell has a slightly different discharge curve than the depleted OEM cell the camera last learned from. When the back reads a voltage mid-charge on an uncalibrated cell, it can flag low or dead battery even though the cell has capacity left. One full charge cycle through the OEM charger resets the reference point. After that single cycle, the indicator tracks correctly against the new cell's actual discharge curve.

Battery percentage jumping erratically on the Leaf back display

If the percentage readout jumps — say, from 80% down to 40% and back — the BMS has not yet mapped the replacement cell's discharge curve. This is a calibration gap, not a faulty cell. Drain the battery until the back shuts down, then charge it uninterrupted to 100% via the OEM charger. After one full cycle, the voltage steps the camera uses for percentage calculation align to the new cell, and the display stabilises.