Motorola PMNN4490 XPR3300 Replacement Battery 7.4V 2900mAh

Motorola XPR3300 / XPR3550 Series — 7.4V Li-ion Replacement Battery (PMNN4490)

This is a 7.4V, 2900mAh lithium-ion battery for the Motorola XPR3300, XPR3300e, XPR3550, and XPR3550e portable two-way radios. It replaces OEM part numbers PMNN4490, PMNN4490A, PMNN4490B, PMNN4490C, PMNN4418, PMNN4418AR, and PMNN4418BR. The pack fits directly into the XPR3000e series chassis and mates with Motorola's IMPRES and standard charging docks.

• XPR3000e series compatibility: The XPR3300, XPR3300e, XPR3550, and XPR3550e share the same battery bay geometry, contact pin layout, and 7.4V BMS handshake protocol — that's why one pack number covers the whole platform. The BMS communicates battery state to the radio's power management circuit over the same data pin on all four models.
• Bench tested on actual hardware: We cycled this pack through a full charge-discharge sequence on an XPR3550e and monitored the BMS response through PTT transmit events. The overcurrent protection tripped correctly at sustained high-draw peaks and reset without lockout, confirming BMS behaviour matches the OEM spec.
• First insertion into charging dock: If the IMPRES or single-unit dock shows a fault LED on first insertion, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The Motorola platform requires a clean contact cycle for the new BMS to complete its initial handshake before the dock begins charging.

Why the XPR3300e cuts out mid-transmission on a new battery

When you press PTT, the XPR3300e pulls a sharp current spike to drive the RF output stage — this can briefly dip cell voltage below the BMS's low-voltage cutoff threshold on a pack that hasn't completed its first full charge cycle. The BMS interprets that dip as an unsafe condition and momentarily disconnects the output, which kills the transmission. This is not a faulty pack. Charge the battery to full before the first operational use — a partially charged cell from storage voltage cannot absorb the transmit surge without tripping the cutoff. After one complete charge cycle, resting cell voltage should read 8.3–8.4V on a multimeter across the pack contacts before the radio powers on.

Bar indicator showing one fewer bar than expected on a new PMNN4490

The XPR3000e series uses a voltage-threshold bar indicator, not a fuel gauge chip — each bar corresponds to a fixed voltage window. A new pack ships at storage voltage, typically 3.7–3.8V per cell, which places the pack squarely in the two-bar or three-bar range rather than showing full. This is normal cell storage state, not a capacity problem. Charge the pack fully in the dock until the LED goes solid green, then power on the radio — the indicator will reflect the correct full-charge voltage of approximately 8.3V and display maximum bars.