Vertex Standard FNB-82LI Replacement Battery 3.7V 1050mAh

Vertex Standard FT-2E / VX-2 / VX-3 Series — 3.7V Li-ion Replacement Battery (FNB-82LI)

This is a 3.7V, 1050mAh lithium-ion replacement battery for the Vertex Standard FT-2E, VX-2, VX-2R, and VX-3 handheld transceivers. It replaces OEM part FNB-82LI and also cross-references E-DC-21 and BC-8260. The pack slots directly into the radio's battery bay using the original locking tab and contact strip.

• FT-2E / VX-2 / VX-3 platform fit: These radios share the same 3.7V single-cell architecture, battery bay dimensions, and four-pad contact layout. One pack covers the whole family because the BMS handshake operates on the same voltage rail and connector pinout across all listed models.
• Bench tested on actual hardware: We ran this pack through insertion, charge acceptance, and PTT transmit-load cycles on the VX-2R. The BMS accepted the charger handshake on first dock insertion and held voltage within spec through repeated transmit bursts without triggering overcurrent cutoff.
• First insertion on the Vertex dock: If the dock LED shows a fault on first seating, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The Vertex charging platform requires a clean contact cycle to complete the BMS handshake before charge current begins.

Why the FT-2E cuts out mid-transmission on a freshly inserted pack

New lithium-ion cells ship at storage voltage — typically 3.6V to 3.65V, not a full 3.7V charge. When you key up on the FT-2E, transmit current spikes sharply. If the cell is at storage voltage, that spike can pull the terminal voltage below the BMS overcurrent threshold and trip a brief cutoff, which the radio reads as a drop-out. The fix is to fully charge the pack before first use. Once the cell is at a full state of charge, the voltage headroom is sufficient to absorb the PTT current spike without triggering the BMS.

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

The VX-2 and VX-3 use a voltage-threshold bar indicator — each bar corresponds to a fixed voltage step. A new pack on its first charge cycle may not reach peak cell voltage immediately because the cell's internal resistance is still settling. This shows as one bar short on the display even though the charger has gone green. Run one full charge-discharge-charge cycle and the cell voltage at end-of-charge will stabilise at 4.2V, which maps correctly to the top bar on the indicator.