Fujifilm NP-70 FinePix F20 Compatible Battery 3.7V 1150mAh

Fujifilm FinePix F20 / F40fd / F47fd — 3.7V Li-ion Replacement Battery (NP-70)

This is a 3.7V, 1150mAh Li-ion replacement for the Fujifilm NP-70 battery. It fits the FinePix F20, F40fd, F45fd, and F47fd compact digital cameras. Swap it in when the original cell no longer holds a useful charge or fails to power the camera at all.

• FinePix F20 / F40fd / F45fd / F47fd compatibility: These four models share the same NP-70 footprint, 3.7V nominal rail, and contact layout. The BMS in each body reads cell voltage through the same two-pin communication path, so one cell covers all four.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on FinePix-class bodies. The BMS accepted the cell without a rejection flag, and the protection circuit tripped correctly at the low-voltage cutoff threshold — no runaway discharge.
• First-use charge cycle on FinePix bodies: Charge this cell inside the camera body or OEM charger before your first shoot. Some FinePix BMS firmware maps the battery-remaining indicator against a full charge baseline — skipping this step can cause the indicator to read inaccurately from the start.

Flash recycling draw and what it does to cell voltage on the F40fd

The F40fd's built-in flash pulls a short, high-current burst each time the capacitor recharges between shots. On a cell that is near the end of its discharge curve, this burst causes a momentary voltage dip that can trip the BMS before the cell is genuinely empty. The camera may show a low-battery warning or shut down even though resting cell voltage is still above 3.5V. Letting the camera sit for 10–15 seconds allows the voltage to recover and the body to resume normal operation. This is a cell-chemistry behaviour, not a fault with the replacement.

Battery percentage jumping erratically on the FinePix display

The FinePix indicator maps voltage thresholds to bar segments rather than reading a fuel gauge IC. A new cell has a slightly different discharge curve than the aged OEM cell the firmware was calibrated against. This makes the indicator skip segments or jump during the first few cycles. Run two to three full charge and discharge cycles through the camera body and the indicator stabilises as the BMS recalibrates its threshold mapping. After conditioning, the display should hold steady until the cell drops below 3.5V.