Fujifilm NP-T125 Replacement Battery 10.8V 1300mAh Li-ion

Fujifilm GFX 50S / Medium Format GFX — 10.8V Li-ion Replacement Battery (NP-T125)

This is a 10.8V, 1300mAh Li-ion replacement for the Fujifilm NP-T125 battery. It fits the GFX 50S and Medium Format GFX camera bodies. Capacity matches the OEM spec at 14.04Wh.

• GFX platform compatibility: The GFX 50S and broader GFX line share the same NP-T125 form factor, connector pinout, and BMS handshake protocol. That shared architecture means one cell covers both bodies without modification.
• Bench tested on actual hardware: We cycled this cell through the GFX body charger and an OEM-compatible external charger. The BMS accepted the cell on first insertion, reported state-of-charge correctly, and held voltage through sustained burst shooting sequences.
• First-cycle BMS calibration on the GFX body: Run the first full charge through the GFX camera body itself, not an external charger. The GFX BMS writes calibration data during an in-body charge cycle, and skipping this step can cause the battery-remaining indicator to read incorrectly from the first shot.

Why the GFX 50S reports a lower battery percentage than expected mid-shoot

The GFX body maps remaining charge by tracking voltage against a discharge curve calibrated to the original NP-T125 cell. A new replacement cell has a slightly different discharge curve until it completes a full break-in cycle. During that initial period, the camera may report a steeper percentage drop than the actual state-of-charge warrants. After two to three full charge-discharge cycles, the BMS recalibrates and the display stabilises. If it doesn't settle by cycle three, charge fully in-body to 10.8V and discharge through normal shooting before checking again.

GFX body showing dead battery indicator on a replacement cell that still has charge

This happens when the BMS has not yet authenticated the new cell's internal resistance signature — common on first insertion. The camera interprets an unfamiliar resistance profile as a depleted or faulty cell and blocks operation. Remove the battery, reinsert it once, then place the body on charge for a full cycle without interrupting it. If the indicator still triggers after a complete in-body charge, check that resting voltage at the cell terminals reads at least 10.8V before reinserting.