Sony NP-FZ100 Replacement Battery 7.4V 1600mAh Li-ion

Sony A7 Mark 3 / A7R Mark 3 / Alpha 1 — 7.4V Li-ion Replacement Battery (NP-FZ100)

This is a 7.4V, 1600mAh Li-ion replacement for the Sony NP-FZ100 battery. It fits the A7 Mark 3, A7R Mark 3, Alpha 1, Alpha 7C, and over 50 additional Sony mirrorless bodies. The cell powers the sensor, autofocus processor, and in-body image stabilisation system.

• Cross-body compatibility on the Alpha platform: All listed models share the NP-FZ100 battery slot, voltage rail, and BMS communication protocol. Sony standardised this form factor across its full-frame mirrorless lineup from 2017 onward, so one cell fits each body without modification.
• Bench tested on actual hardware: We ran this cell in an A7 Mark 3 body through full charge and discharge cycles. The BMS handshake completed correctly, battery percentage displayed without error, and the protection circuit tripped at the expected low-voltage threshold.
• First-cycle BMS acceptance: On first install, charge this battery fully inside the camera body or via Sony's OEM multi-battery charger before shooting. Some Alpha bodies require one complete in-body charge cycle to accept a new cell and display accurate battery-remaining figures.

Battery percentage jumping erratically on the Alpha 7 display

Sony's fuel gauge maps voltage steps against a discharge curve calibrated to the original NP-FZ100 cell. A new replacement cell has a slightly different discharge curve shape, so the camera's indicator can read ahead or behind the actual state of charge. This shows up most often as the percentage dropping quickly from 100% then stabilising, or jumping between two values mid-shoot. Running two full charge-discharge cycles in the camera body lets the BMS recalibrate its threshold mapping to the new cell. After that, percentage tracking typically settles within a few percent of actual charge level.

Flash not fully recycling between shots with a new battery

The flash capacitor draws a high recharge current immediately after each exposure — far above the steady-state draw of autofocus or image processing alone. If the replacement cell's internal resistance is elevated, voltage sags during that recharge spike, and the camera delays the next shot or shows a slow recycle indicator. This is not a BMS fault — it is a cell-quality issue visible at the terminal voltage level. Check cell voltage under load with a multimeter: a healthy NP-FZ100-format cell should hold above 7.0V during a flash-capacitor recharge cycle. If voltage drops below that, the cell is not meeting spec.