Yaesu FNB-V103 VX-231 Replacement Battery 7.4V 2600mAh

Yaesu VX-231 / VX-234 Series — 7.4V Li-ion Replacement Battery (FNB-V103LI)

This is a 7.4V, 2600mAh lithium-ion battery for the Yaesu VX-231, VX-230, VX-231L, and VX-234 handheld VHF transceivers. It cross-references OEM part numbers FNB-V103, FNB-V103LI, FNB-V104, FNB-V104LI, FNB-V131Li, and FNB-V132Li. The pack slots into the standard battery bay and connects via the same multi-pin contact strip as the original.

• VX-230 / VX-231 / VX-234 platform fit: These models share a common 7.4V battery bay, connector pitch, and BMS handshake protocol. One pack covers the full series because the charger dock negotiates with the BMS over the same contact strip across all four variants.
• Bench tested on actual hardware: We ran this pack on a VX-231 with the standard desktop charger. The BMS accepted the dock handshake on first insertion, the charge cycle completed without fault LED, and transmit current draw stayed within the rated window under sustained PTT.
• First insertion on the Vertex Standard dock: If the dock shows a fault LED on first insertion, pull the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The dock requires a clean contact cycle to accept the BMS handshake before charging begins — a single re-seat resolves this in most cases.

Why the VX-231 cuts out mid-transmission on a freshly fitted pack

The VX-231 draws a sharp current spike the moment PTT is pressed — RF output hits near-full power in under 50 milliseconds. A new pack shipped at storage voltage (typically around 3.7V per cell) has a higher internal impedance than a fully charged cell. At that impedance, the transmit spike can trip the BMS overcurrent threshold before the radio completes the key-up sequence. The fix is straightforward: charge the pack to full before the first transmit session. A full charge brings cell impedance down and gives the BMS enough headroom to pass the PTT spike cleanly.

Bar indicator showing one fewer bar than expected after fitting this pack

The VX-231 reads battery state from voltage thresholds, not a fuel gauge chip. A new pack at storage voltage — around 7.4V resting — sits at the boundary between the second and third bar threshold on most firmware versions. This is not a fault. Put the pack through one full charge cycle on the desktop dock until the charge LED goes green, then check the indicator again. After a full charge the resting voltage rises to approximately 8.3–8.4V and the display will show the correct full-charge bar level.