Leaf AFi-II 7 Camera Compatible Battery 7.4V 3700mAh

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

This is a 7.4V, 3700mAh (27.38Wh) Li-ion battery for the Leaf AFi-II 7 and Aptus series medium format digital backs. It fits the AFi-II 7, Aptus 22, Aptus 65, Aptus 75, and seven additional Aptus models. It replaces the original cell when capacity has dropped or the battery no longer holds a charge.

• AFi-II 7 and Aptus compatibility: These models share the same battery form factor, contact layout, and 7.4V power rail. The BMS inside the digital back reads the same charge state regardless of which Aptus variant or AFi-II body you're running.
• Bench tested on actual hardware: We cycled this cell through charge and discharge under a controlled load matching medium format digital back draw. The BMS responded correctly at both high-capacity and low-voltage cutoff thresholds — no false shutdowns at either end.
• First-use charge cycle on the AFi-II 7: Seat this battery and run one full charge cycle directly through the camera body or OEM charger before shooting. The Leaf BMS maps its battery-remaining display against the discharge curve during that first cycle — skipping it causes the indicator to read inaccurately from the start.

Why the Leaf AFi-II 7 battery indicator reads wrong after a cell swap

The AFi-II 7 maps its fuel gauge against a stored discharge curve calibrated during the first charge cycle after a new cell is seated. A replacement cell with a slightly different internal resistance profile will cause the indicator to jump or plateau mid-discharge until the BMS recalibrates. This is not a fault with the replacement cell — it's the BMS learning the new curve. Run one full charge-to-4.2V, discharge-to-3.0V cycle and the gauge stabilises. If it doesn't settle after two cycles, check that you're charging via the OEM charger, not a third-party unit with non-standard termination voltage.

Digital back showing dead battery indicator on a partially charged replacement cell

This happens when the replacement cell's resting voltage drops below the Leaf body's recognition threshold — typically around 3.0V per cell, or 6.0V combined — after a period of storage. A deeply discharged Li-ion cell can read as absent rather than flat to the camera's BMS. Pull the battery, place it in the OEM Leaf charger externally for 15–20 minutes to pre-charge it above the 6.0V floor, then reinsert it into the body. Once the body sees a voltage above threshold, it will accept the cell and charge normally.