Motorola PMNN4065 MotoTRBO DP3400 Compatible Battery 7.5V 2600mAh

Motorola MotoTRBO DP3400 Series — 7.5V Li-ion Replacement Battery (PMNN4065)

This 7.5V, 2600mAh Li-ion battery replaces the OEM pack on the Motorola MotoTRBO DP3400, DP3401, DP3600, and DP3601, along with more than 49 additional MotoTRBO models. It carries the same voltage rail and connector footprint as PMNN4065, PMNN4066, NNTN4077, and the broader PMNN4104 family. Capacity is 2600mAh (19.5Wh), matching the original factory specification.

• DP3400 / DP3600 platform fit: The DP3400 and DP3600 share the same 7.5V battery bay, contact layout, and BMS handshake protocol. One pack covers both form factors without modification — the connector seats identically and the radio's BMS accepts the pack on first insertion when contacts are clean.
• Bench tested on actual hardware: We cycled this pack through a full charge and a sustained transmit load on the DP3400 platform. The BMS held the voltage rail steady through the PTT current spike and released cleanly at end-of-discharge without tripping an overcurrent lockout.
• First insertion into the IMPRES or standard Motorola dock: If the dock shows a fault LED on first seating, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The Motorola dock requires a clean contact cycle to complete the BMS handshake before it will begin charging — a single reseating clears this in almost every case.

Why the DP3400 cuts out mid-transmission on a new battery

The DP3400 draws a short, sharp current spike the moment PTT is pressed — RF output demands significantly more current than standby. If the BMS detects that spike as an overcurrent event, it trips a temporary protection cutoff and the radio goes silent. This is not a fault with the radio. It happens when cell impedance is elevated — either from a pack that has been in storage at low voltage or from a counterfeit cell with inadequate discharge headroom. A genuine Li-ion cell at or above 7.2V handles the PTT spike without tripping the BMS. Fully charge the new pack before the first field shift so the cells start above the BMS overcurrent threshold.

Bar indicator showing one fewer bar than expected after fitting a new pack

The DP3400 reads battery level from voltage thresholds — it has no charge-counting circuitry. A pack shipped at storage voltage (typically around 3.7V per cell) will show one or two bars even though the cells are not depleted. This is normal behaviour for a new Li-ion pack that has not yet received a full charge. Place the pack in the charger dock and run a complete charge cycle to bring both cells to 4.2V. After that first full charge, the bar indicator will reflect actual charge state accurately.