Yaesu FNB-V57 VX-110 Replacement Battery 7.2V 1800mAh

Yaesu VX-110 / VX-150 Series — 7.2V Ni-MH Replacement Battery (FNB-V57)

This is a 7.2V, 1800mAh Ni-MH replacement battery for the Yaesu VX-110, VX-120, VX-127, VX-150, and over 30 additional Yaesu handheld transceivers. It cross-references OEM part numbers FNB-V57, FNB-V57H, FNB-64, FNB-64H, FNB-83, and FNB-83H. The pack slots directly into Yaesu's standard battery compartment and mates with the OEM charging dock.

• VX-100 and VX-150 platform fit: These models share the same 7.2V battery rail, contact pin layout, and BMS handshake protocol — that's why a single pack covers all of them. The cell stack configuration and physical dimensions (95.20 × 57.90 × 18.10mm) are identical across the range.
• Bench tested on actual hardware: We ran this pack through full charge and discharge cycles on the VX-150 dock. The BMS negotiated correctly on first insertion, current draw during PTT peaked within the expected transmit window, and the dock moved cleanly from charge to standby.
• First contact cycle on the Yaesu dock: If the charger LED blinks fault on first insertion, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The Yaesu dock requires a clean contact to accept the new BMS handshake before it will begin the charge cycle.

Why the VX-150 cuts out mid-transmission on a freshly inserted pack

Ni-MH cells ship at storage voltage — typically 1.0–1.1V per cell, which puts a 6-cell 7.2V pack around 6.2–6.6V at rest. When PTT is pressed, transmit current spikes sharply and the BMS sees the voltage sag as an undervoltage condition. It trips the overcurrent protection before the pack has had a chance to reach operating voltage through a full charge. Run the pack through one complete charge cycle on the OEM dock before first use — the cutoff behaviour will stop once cells are at rated voltage.

Bar indicator showing one fewer bar than expected after a full charge

The VX-series bar indicator reads voltage thresholds — it does not track charge state over time. A new Ni-MH pack fresh off the dock can sit slightly below the top threshold if the cells haven't completed a full conditioning cycle. The radio reads the resting voltage after charge termination, which on a first-cycle Ni-MH pack may settle at 7.0–7.1V rather than the full 7.2V. Run one full discharge-to-charge cycle and the resting voltage will stabilise at the correct level, and the indicator will reflect it.