Vertex Standard VX-351 Compatible Battery 7.4V 2600mAh

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

This 7.4V 2600mAh Li-ion pack replaces the FNB-V130LI in the Vertex Standard VX-351, VX-354, and VX-359 portable two-way radios. These radios are common across security, emergency services, and professional comms teams. Capacity is 2600mAh (19.24Wh) — use that figure for any duty-cycle planning, not third-party estimates.

• VX-351 / VX-354 / VX-359 platform fit: All three models share the same battery bay dimensions, contact pin layout, and BMS handshake protocol — one pack covers the range without any adapter or modification.
• Bench tested on actual hardware: We ran this pack through the Vertex Standard charger dock and confirmed the BMS handshake completes correctly — charge LED transitions from red to green without fault interruption, and the overcurrent circuit holds under simulated PTT transmit load.
• First insertion on the VX-series dock: If the dock shows a fault LED on first insertion, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The VX-series dock requires a clean contact cycle to accept the new BMS before charging begins — this is a contact issue, not a faulty cell.

Why the VX-351 cuts out mid-transmission on a new FNB-V130LI

PTT transmit on the VX-351 draws a short current spike — typically 1.5–2A — as the RF stage fires up. A new pack shipped at storage voltage (around 3.7V per cell) has higher internal impedance than a fully charged cell. That impedance causes a momentary voltage sag, which can trip the BMS overcurrent threshold before the cell reaches operating charge. Charge the pack fully before first use — the dock needs to see the cell above 7.0V total to hold the charge cycle open.

Bar indicator showing one fewer bar than expected after fitting the FNB-V130LI

The VX-series bar indicator reads voltage thresholds directly — it does not track charge state through a counting chip. A new cell at storage voltage sits below the top threshold, so the radio displays one bar fewer than full even with a brand-new pack installed. This is not a capacity fault. Run a full charge cycle through the Vertex Standard dock and let the cell reach 8.4V before drawing conclusions — the indicator will step up to the correct bar level once voltage is there.