Curtis Mathes F690 Camera Replacement Battery 6V 2100mAh

Curtis Mathes F690 / F820 / FV600 / FV900 Series — 6V 2100mAh Ni-MH Replacement Battery

This is a 6V, 2100mAh Ni-MH replacement battery for Curtis Mathes camcorders including the F690, F820, FV600, and FV900. It replaces the original pack when capacity has dropped or the cell has failed entirely. Capacity figure is 2100mAh (12.6Wh) as rated for this series.

• F690 / F820 / FV-series compatibility: These models share the same 6V power rail, physical connector, and BMS communication protocol — one cell format covers the full group without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the F690 body. The BMS accepted the pack, voltage regulation held within spec across the discharge curve, and no fault codes were triggered.
• First-install charge cycle on camcorder body: Run the first full charge inside the camera body or OEM charger before shooting. Some Curtis Mathes BMS firmware will not map the battery-remaining display accurately until it completes one internal calibration cycle from a full charge.

Why the F690 battery indicator reads full then drops suddenly mid-recording

Ni-MH cells have a flatter discharge curve than Li-ion. The F690's battery gauge is calibrated to detect voltage drop thresholds, but a new cell — or one that hasn't completed a calibration cycle — doesn't map cleanly to those thresholds yet. The gauge reads high until the cell hits a voltage knee, then drops fast. One full charge-discharge cycle inside the camera body lets the BMS re-map the curve. After that cycle, the indicator tracks remaining capacity accurately.

Camcorder shuts down mid-clip even though the indicator showed charge remaining

This usually points to voltage sag under the combined draw of the image sensor, recording processor, and viewfinder running simultaneously. The battery resting voltage looks fine, but under full recording load it dips below the BMS cutoff threshold. Check that the cell has been fully charged — a partially charged Ni-MH pack sags faster under sustained load. If the shutdown repeats from a confirmed full charge, let the pack cool to room temperature and retry; Ni-MH cells lose output voltage noticeably below 15°C.