Kenwood KNB-L1 P25 Replacement Battery 7.4V 3300mAh

Kenwood P25 / TK-5230 / TK-5330 / TK-5430 — 7.4V Li-ion Replacement Battery (KNB-L1)

This is a 7.4V, 3300mAh Li-ion battery pack for the Kenwood P25 series and TK-5230, TK-5330, and TK-5430 portable two-way radios. It replaces OEM part numbers KNB-L1, KNB-L2, KNB-L3, KNB-N4, KNB-L2M, KNB-L3M, KNB-LS5, KNB-LS6, and KNB-N4M. Capacity is 3300mAh (24.42Wh).

• P25 and TK-5000 series compatibility: These models share the same 7.4V battery bay, connector pin-out, and BMS handshake protocol. One battery pack covers the full radio family without modification.
• Bench tested on actual hardware: We cycled this pack through transmit loads on a TK-5330 and confirmed the BMS held voltage through sustained PTT bursts. No overcurrent trips occurred during the test sequence.
• First insertion into the charger dock: If the dock shows a fault LED on the first insertion, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The Kenwood platform requires a clean contact cycle to complete the BMS handshake before it will begin charging.

Why the TK-5230 drops to reduced TX power mid-shift on a new KNB-L1

New Li-ion cells ship at storage voltage — typically around 3.7V per cell, not the 4.2V full-charge ceiling. Under a sustained RF transmit load, that lower starting voltage sags further, and the radio's power management circuit steps down output to protect the BMS. This is not a faulty pack. A full charge cycle before the first shift brings each cell to 4.2V and eliminates the sag under transmit load. After that first proper charge, TX power holds at the rated level through a normal working day.

Bar indicator showing one fewer bar than expected after fitting a new KNB-L1

The P25 series uses a voltage-threshold bar indicator, not a fuel gauge chip. If the new pack arrives at storage voltage rather than full charge, the radio reads the lower voltage and displays one bar fewer than a fully charged pack would show. This is expected behaviour for a cell that has not yet been fully charged. Put the pack through a complete charge cycle in the Kenwood dock until the LED goes solid green, then reinsert — the indicator will reflect the correct charge state at 7.4V full.