About this replacement
Fujifilm FinePix F420 Zoom — 2.4V Ni-MH Replacement Battery (NH-20)
This is a 2.4V, 1200mAh Ni-MH cell built to the NH-20 specification. It fits the Fujifilm FinePix F420 Zoom and FinePix F420 compact digital cameras. The cell slots into the same battery compartment as the original and connects to the camera's power circuit without modification.
- FinePix F420 and F420 Zoom compatibility: Both models run the same 2.4V power rail and use the identical NH-20 battery form factor — same footprint at 44.50 × 21.80 × 10.35mm, same connector orientation, same BMS interface. One cell covers both variants.
- Bench tested on actual hardware: We cycled this cell through the F420's charge circuit and monitored BMS handshake. The camera accepted the cell without error flags, and the charge cycle completed cleanly at full capacity termination.
- First-use charge protocol for the F420: Insert the new cell and run a full charge cycle through the camera body or OEM charger before your first shoot. The F420's battery-remaining display calibrates its voltage thresholds during that first cycle — skipping it causes the indicator to read low or jump erratically early on.
Dead battery indicator on the F420 with a partially charged replacement cell
The F420 maps its battery gauge to a fixed voltage-threshold curve tuned to a fully conditioned Ni-MH cell. A new or recently stored replacement cell may sit at a resting voltage that the camera interprets as depleted — even when actual charge is present. This is a calibration mismatch, not a faulty cell. Run one full charge cycle from within the camera body or OEM charger, and the indicator will reset to match the cell's actual discharge curve.
Flash not fully recycling between shots on a new NH-20 cell
Flash recycling draws a sharp current spike to recharge the capacitor after each firing. If the replacement cell hasn't completed a conditioning cycle, its internal resistance is temporarily higher than a broken-in cell — this slows capacitor recharge and extends the recycle gap between shots. The symptom usually clears after two or three full charge-discharge cycles. If it persists beyond that, check resting voltage after a full charge — it should read at or above 2.4V.