Hytera PCN550 Compatible Battery 3.8V 4000mAh

Hytera PCN550 — 3.8V Li-Polymer Replacement Battery (BP4003)

This is a 3.8V 4000mAh lithium-polymer battery built to replace the BP4003 in the Hytera PCN550 portable digital radio. The PCN550 is a professional-grade land mobile radio used in public safety, security, and enterprise communications. Voltage and capacity match the original spec exactly.

• PCN550 platform fit: The PCN550 uses a slim lithium-polymer pack at 3.8V with a proprietary contact layout and BMS handshake. This battery matches that voltage rail and connector orientation so the radio's power management circuit accepts it without throwing a fault state.
• Bench tested on actual hardware: We cycled this pack through full charge and discharge on the PCN550 platform. The BMS handled PTT transmit current spikes without triggering overcurrent cutoff, and the charger dock accepted the pack and progressed to charge on first insertion.
• Contact strip condition on first install: If the charger dock shows a fault LED on first insertion, remove the BP4003, wipe the gold contact strip with a dry cloth, and reseat firmly. The PCN550 platform requires a clean contact cycle before the dock accepts the new BMS handshake and begins charging.

PCN550 cutting out mid-transmission on a freshly inserted BP4003

When you press PTT, the PCN550 draws a sharp current spike to power the RF transmitter — this is the highest load the battery sees in normal operation. A new lithium-polymer pack shipped at storage voltage (typically around 3.6–3.65V per cell) can trigger the BMS overcurrent threshold under that spike before the cell is fully charged. The fix is straightforward: charge the BP4003 to full before the first use rather than inserting a pack straight from the box. Once the cell sits at or above 3.8V, the transmit spike stays within BMS limits and the cutout stops.

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

The PCN550 reads battery level through voltage thresholds, not a fuel gauge chip. A new cell often stabilises slightly below the threshold for the top bar display immediately after its first charge, because the cell hasn't been through a full conditioning cycle yet. This is not a capacity defect — the usable energy is there, the voltage just hasn't settled at peak resting level. Run one full discharge and recharge cycle and the resting voltage will rise to where the top bar threshold registers correctly.