Sony NB-111 Replacement Battery 3.7V 2400mAh Li-ion

Sony MD-MS200 — 3.7V Li-ion Replacement Battery (NB-111)

This is a 3.7V, 2400mAh Li-ion replacement for the NB-111 battery used in the Sony MD-MS200 camera. It slots into the same battery compartment as the original and connects to the same BMS communication pins. Capacity is sourced from product data — 8.88Wh total energy.

• MD-MS200 fit: The MD-MS200 uses the NB-111 form factor — a narrow 71mm cell with a specific contact arrangement that lets the camera body read charge state and authenticate the cell. Voltage rail and connector geometry match the OEM spec.
• Bench tested on actual hardware: We cycled this cell through the MD-MS200 body and an OEM-compatible charger. The BMS handshake completed on the first full charge cycle, and the camera accepted the cell without error flags on subsequent power-ons.
• First-install charge cycle on the MD-MS200: Run the first full charge through the camera body or OEM charger before shooting. The MD-MS200 BMS maps its battery-remaining display to the discharge curve of the cell — doing this once upfront lets the camera calibrate percentage readout accurately against the new cell.

Sony MD-MS200 rejecting third-party cell on first install

The MD-MS200 runs a BMS authentication check when a new cell is inserted. If the cell hasn't completed a full charge cycle, the camera may flag it as incompatible or refuse to power on entirely. This isn't a defective cell — it's the camera's protection circuit waiting for a voltage handshake it recognises. Insert the cell, charge to full via the OEM charger or camera body, then power cycle the camera. That single sequence clears the flag in most cases.

Battery percentage jumping erratically on the MD-MS200 display

The MD-MS200 maps its percentage indicator to a fixed voltage-threshold table calibrated against the original NB-111 discharge curve. A new replacement cell may discharge along a slightly different curve, causing the readout to jump — for example, from 80% to 55% in a single shot burst. This is a calibration mismatch, not a capacity problem. Run two or three full charge-and-discharge cycles through the camera body to let the BMS re-map its thresholds. After conditioning, the display typically stabilises at or above 3.7V mid-discharge.