Motorola PMNN4423A Mag One Q5 Replacement Battery 7.4V 1100mAh

Motorola Mag One Q5 / Q9 / Q11 / VZ-9 — 7.4V Li-ion Replacement Battery (PMNN4423A)

This is a 7.4V 1100mAh Li-ion battery replacing OEM part PMNN4423A. It fits the Motorola Mag One Q5, Q9, Q11, and VZ-9 two-way radios — compact business-band portables used in hospitality, security, and retail environments. Capacity is 1100mAh (8.14Wh), matching the original pack specification.

• Mag One Q5 / Q9 / Q11 / VZ-9 platform fit: These four models share the same battery bay geometry, contact pin layout, and BMS handshake protocol — a single pack design services all of them. The 7.4V nominal voltage rail is common across the Mag One compact series.
• Bench tested on actual hardware: We ran the PMNN4423A replacement through full charge-discharge cycles on Q5 hardware. The BMS accepted the charger dock handshake on first insertion, cell voltage held stable through PTT transmit bursts, and the protection circuit tripped correctly at the low-voltage cutoff threshold.
• First insertion on the Mag One dock: If the dock LED shows amber fault on first seating, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The Mag One charger dock requires a clean contact cycle to complete the BMS handshake before it begins the charge sequence.

Why the Mag One Q5 cuts out mid-transmission on a freshly inserted battery

The Q5 draws a sharp current spike the moment PTT is pressed — transmit current is significantly higher than standby draw. A new cell shipped at storage voltage (typically 3.7–3.8V per cell) has not yet been conditioned, so the BMS may trip the overcurrent protection on that first transmit spike. This is not a faulty pack. Running one full charge cycle through the dock before field use brings the cell voltage to the 4.1–4.2V working range, which gives the BMS enough headroom to pass the transmit surge without tripping.

Bar indicator showing one fewer bar than expected after fitting new PMNN4423A

The Mag One platform reads battery level using voltage thresholds — it has no cycle counter or impedance tracking. A new cell at storage voltage sits below the top threshold, so the radio displays one bar low even with a full physical charge capacity available. This is not a calibration problem. Seat the pack in the dock and run one complete charge to 8.4V (4.2V per cell) — the bar indicator will read correctly from the next power-on.