Vertex Standard VXD720 Compatible Battery 7.4V 3350mAh Li-ion

Vertex Standard VXD720 — 7.4V Li-ion Replacement Battery

This 7.4V 3350mAh lithium-ion battery replaces the original pack in the Vertex Standard VXD720 portable two-way radio. It fits the VXD720 directly, using the same connector and BMS handshake the dock expects. Capacity figures come from the product data — 3350mAh at 24.79Wh.

• VXD720 platform fit: The VXD720 uses a 7.4V two-cell Li-ion architecture. The dock accepts packs that pass a BMS handshake on first insertion — voltage rail, connector pinout, and cell count all have to match before the charger begins. This pack meets those parameters.
• Bench tested on actual hardware: We cycled this pack through full charge and discharge on a VXD720-class dock. The BMS responded correctly to PTT-triggered transmit surges without tripping overcurrent protection, and the voltage held steady through sustained RF output.
• First insertion contact check: If the dock shows a fault LED when you first seat this battery, remove it, wipe the gold contact strip with a dry cloth, and reseat firmly. The VXD720 platform requires a clean contact cycle to complete the BMS handshake before charging begins.

Why the VXD720 cuts out mid-transmission on a new battery

A new Li-ion pack ships at storage voltage — typically around 3.7V per cell, not the full 4.2V. When the radio transmits, it draws a sharp current spike. If cell voltage is already low, the BMS reads an undervoltage condition during that spike and cuts power to protect the cells. The radio goes silent even though the pack reads as charged on the indicator. A full charge cycle before field use eliminates this — the cells need to reach at least 8.0V combined before sustained TX is reliable.

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

The VXD720 uses a voltage-threshold bar indicator, not a fuel gauge chip. Each bar corresponds to a voltage window. A new pack at storage voltage sits in a lower window than a fully charged cell, so the display shows one or two bars even though the pack is not depleted. Charge the battery completely in the dock before reading the indicator — once cells reach full charge voltage, the display will reflect the correct state.