Sony NP-FV50A Camcorder Replacement Battery 7.3V 1030mAh

Sony FDR-AX40 / FDR-AX45 / HDR-CX625 — 7.3V Li-ion Replacement Battery (NP-FV50A)

This is a 7.3V, 1030mAh Li-ion replacement for the Sony NP-FV50A battery. It fits the FDR-AX40, FDR-AX45, FDR-AX60, HDR-CX625, and nine additional Sony camcorder models. Use it as a direct swap when your original cell no longer holds a usable charge.

• FDR-AX and HDR-CX series compatibility: These models share the NP-FV50A form factor, the same 7.3V rail, and an identical multi-pin connector layout. The BMS handshake protocol is consistent across this lineup, so one cell serves the full range without adapter or modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a Sony FDR-AX40 body. The BMS accepted the cell on first install, reported charge state correctly, and protection circuits triggered at the expected low-voltage cutoff point.
• First-install charge cycle on the FDR-AX40: Run one full charge through the camera body or OEM charger before shooting. The FDR-AX40's battery management system maps its remaining-charge display against a discharge curve — skipping this step can cause the indicator to read inaccurately for the first several cycles.

Why the FDR-AX40 battery percentage jumps erratically with a new cell

Sony's remaining-battery indicator on the FDR-AX40 maps voltage thresholds to a discharge curve it learned from previous cells. A new Li-ion cell has a slightly different discharge curve during its first few cycles. The camera reads voltage correctly but maps it to the wrong percentage bracket, causing the display to skip from 80% to 40% mid-session. After two or three full charge-discharge cycles, the indicator stabilises and tracks accurately.

FDR-AX40 showing "No Battery" or refusing to power on with a charged replacement

This is a BMS authentication check failing on first contact, not a dead cell. The FDR-AX40 reads a handshake signal from the battery's multi-pin connector before it will power the camera. If the cell was stored at a low state of charge during transit, the initial voltage may sit below the camera's wake threshold. Place the battery in an OEM-compatible charger until the charge indicator confirms at least a partial charge, then reinsert. The camera should power on normally once the cell reads above approximately 6.5V at the connector.