Vertex Standard VX-351 Compatible Battery FNB-V130LI 7.4V 2200mAh

Vertex Standard VX-351 / VX-354 / VX-359 — 7.4V Li-ion Replacement Battery (FNB-V130LI)

This is a 7.4V 2200mAh lithium-ion battery for the Vertex Standard VX-351, VX-354, and VX-359 handheld transceivers. It replaces OEM part numbers FNB-V130LI and FNB-V130LI-UNI. The pack slots into the same battery bay and connects to the same dock charger contacts as the original.

• VX-351, VX-354, VX-359 platform fit: These three models share the same battery bay dimensions, contact layout, and BMS handshake protocol. One pack covers all three — no adapter or firmware change needed.
• Bench tested on actual hardware: We cycled this pack through full charge and transmit-load draws on the VX-351. The BMS handled the PTT current spike cleanly and held voltage above the low-battery threshold throughout the test cycle.
• First insertion into the dock: If the charger shows a fault LED on first insertion, remove the pack, wipe the gold contact strip with a dry cloth, and reseat it firmly. The Vertex platform requires a clean contact cycle to complete the BMS handshake before charging begins.

VX-351 bar indicator showing one fewer bar than expected on a new FNB-V130LI

New lithium-ion cells ship at storage voltage — typically around 3.7V per cell, which puts this 7.4V pack below the threshold the VX-351 maps to a full bar reading. The radio's voltage-threshold indicator reads the resting voltage on insertion, not the pack's actual charge state. A single charge cycle brings the pack to full working voltage. After that first full charge, the bar indicator will read correctly.

Radio drops to reduced TX power mid-shift on the VX-354

Sustained RF output pulls significantly more current than standby or receive modes. If cell impedance rises — common in aged or deeply discharged packs — voltage sags under that transmit load and the radio's protection circuit steps down output power to stay within safe operating range. This is not a radio fault; it is the BMS responding to a real voltage drop. Swapping to a freshly charged pack and confirming resting voltage reads at or above 8.0V before the shift will eliminate this mid-shift drop.