About this replacement
Kenwood NX-200 / NX-300 Series — 7.4V Li-ion Replacement Battery (KNB-47L)
This is a 7.4V, 2500mAh lithium-ion battery for the Kenwood NX-200, NX-300, TK-3320, and TK-5220 series two-way radios. It replaces OEM part numbers KNB-47L, KNB-48L, and KNB-50NC. Dimensions are 105.00 × 57.80 × 25.00mm — matching the original form factor for these portable radios.
- NX-200 / NX-300 / TK-3320 / TK-5220 platform fit: These models share the same battery bay dimensions, 7.4V voltage rail, and contact pin arrangement. The BMS handshake protocol is consistent across this Kenwood platform, so one pack covers the full range without modification.
- Bench tested on actual hardware: We ran this pack through charge cycles on a Kenwood drop-in charger and monitored BMS response during simulated PTT transmit loads. The protection circuit held stable cutoff thresholds at both high-draw transmit bursts and idle standby current draw.
- First-insertion contact cycle on the charger dock: If the 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 BMS requires a clean contact cycle to complete the handshake before the charger accepts the new pack and begins charging.
Why the NX-200 cuts out mid-transmission on a freshly inserted battery
During PTT transmit, the NX-200 draws a sharp current spike — often 1.5A to 2A above the standby draw — that happens in milliseconds. A new cell shipped at storage voltage (typically around 3.7V per cell) has not yet settled to its working voltage range, so the BMS can interpret the transmit spike as an overcurrent event and trip the protection circuit. This is not a faulty battery. Run the pack through one full charge cycle before heavy field use, and the BMS trip threshold will sit comfortably above the transmit surge current.
Bar indicator showing one fewer bar than expected after fitting the KNB-47L
The NX-200 and TK-series radios use voltage-threshold bar indicators — not a fuel gauge chip. A new cell delivered at storage voltage reads lower than a fully charged pack, so the radio displays one fewer bar even though the cell is not depleted. This is not a capacity fault. Charge the battery fully before first use and the voltage will rise to approximately 8.4V, placing it firmly in the top bar threshold. After one complete charge, the bar display will reflect actual charge state accurately.