Kenwood P25 Compatible Battery KNB-L1 7.4V 1800mAh

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

This is a 7.4V, 1800mAh Li-ion replacement battery for the Kenwood P25 series and TK-5000 family 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. It fits radios used in public safety, commercial, and business communications where shift-long operation matters.

• P25 and TK-5000 series fit: The P25, TK-5230, TK-5330, and TK-5430 share the same 7.4V battery bay geometry, contact alignment, and BMS handshake protocol — that is why a single pack covers the full range. Swapping between these models requires no adapter or firmware change.
• Bench tested on actual hardware: We ran this pack on a TK-5330 bench unit and cycled through PTT transmit bursts to confirm the BMS handled the current spike without tripping. The cell voltage held stable under sustained RF output and the charger dock accepted the pack without a fault LED on first insertion.
• First insertion — contact cycle check: If the charger dock shows a fault LED on 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 charging can begin.

Why the TK-5330 drops to reduced TX power mid-shift on a new KNB-L1

The TK-5000 series monitors pack voltage continuously and steps down transmit power when voltage sags under sustained RF load. A new cell shipped at storage voltage — typically around 3.7V per cell — has not yet reached its full charge state, so the radio sees a lower available voltage than expected. This can trigger a premature power reduction that looks like a faulty battery but is not. Fully charge the pack before the first shift and the voltage sag behaviour should resolve after one complete cycle.

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

Kenwood P25 and TK-5000 radios use a simple voltage-threshold bar indicator — each bar corresponds to a voltage band, not a calculated capacity percentage. A new pack at storage voltage reads in the lower threshold band, so the radio displays fewer bars even though the cell is not depleted. This is not a cell fault. Charge the pack to full in the dock and the indicator will move to the correct bar level once cell voltage clears the upper threshold, typically above 8.2V at rest.