About this replacement
Motorola XPR7350 / XPR3000 Series — 7.4V Li-ion Replacement Battery (PMNN4409)
This 7.4V, 3350mAh lithium-ion battery replaces the PMNN4409 and compatible OEM packs across the Motorola XPR7350, XPR3000, XPR3500, and XPR3300 series portable radios. It fits the same physical footprint and connector as the original, and the BMS communicates with the radio's charge management circuitry without modification. Capacity comes from the cell, not the label — 3350mAh at 7.4V nominal.
- XPR / MOTOTRBO platform fit: The XPR3000, XPR3300, XPR3500, and XPR7350 share a common battery bay geometry and the same 7.4V voltage rail. All compatible OEM part numbers — including PMNN4409AR, PMNN4412, PMNN4448, PMNN4490, PMNN4491, PMNN4543, and PMNN4544 variants — map to this same electrical specification, which is why one replacement covers the full group.
- Bench tested on actual hardware: We ran this pack through charge and transmit cycles on the XPR platform. The BMS completed the handshake with the Motorola IMPRES dock without fault, held voltage through sustained PTT bursts, and the overcurrent protection tripped correctly at the rated threshold — not prematurely.
- First insertion into the IMPRES dock: If the dock LED shows a fault on first insertion, remove the pack and wipe the gold contact strip with a dry cloth before reseating. The IMPRES system requires a clean contact cycle to read the BMS data register — a contaminated contact can prevent charge acceptance entirely.
Why the XPR7350 cuts out mid-transmission on a new battery
The XPR7350 draws a sharp current spike the moment PTT is pressed — RF output pulls significantly more current than standby or receive mode. If the BMS registers this as an overcurrent event, it trips and momentarily disconnects the cell, cutting the transmission. On a new pack, this usually happens because the cells shipped at storage voltage (around 3.7–3.8V per cell) rather than full charge. A full charge cycle to 4.2V per cell resolves the trip threshold margin and the cutouts stop.
Bar indicator showing one fewer bar than expected on a fresh PMNN4409
The XPR radio reads battery state through voltage thresholds — each bar on the display corresponds to a voltage band. New cells arrive at storage voltage, not fully charged, so the radio correctly reports fewer bars than a full pack would show. This is not a capacity fault or a cell mismatch. Seat the battery in the charger dock until the LED goes green, then reinsert it into the radio — the bar indicator will reflect the actual full-charge voltage once the pack is topped up to 8.4V across both cells.