About this replacement
Kenwood TK-3200L-U15P Series — 7.4V Li-ion Replacement Battery (KNB-45)
This is a 7.4V, 1800mAh Li-ion replacement battery for the Kenwood TK-3200 and TK-3202 series portable two-way radios. It replaces OEM part numbers KNB-45, KNB-45L, and KNB-45Li across a wide range of UHF handhelds in this family. The cell and BMS are matched to the voltage thresholds the radio's power management circuit expects.
- TK-3200 and TK-3202 platform fit: Both series share the same battery bay geometry, contact layout, and 7.4V nominal rail. The BMS in this pack communicates the same charge-acceptance signal the dock needs — no pin adapter or firmware change required.
- Bench tested on actual hardware: We cycled this pack through repeated PTT-triggered transmit loads to confirm the BMS handles the current spike without tripping overcurrent protection. Voltage held stable across the transmit window.
- First-insertion contact 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 dock requires a clean contact cycle to complete the BMS handshake before charging begins.
Why the TK-3200 cuts out mid-transmission on a new KNB-45
A new Li-ion pack ships at storage voltage — typically around 3.7V per cell, not the full 4.2V. When the radio keys up, transmit current spikes sharply. If the cell hasn't been fully charged first, that spike can pull the pack voltage below the BMS cutoff threshold, causing the radio to drop out mid-transmission. This is not a faulty battery — it's the BMS doing its job on a partially charged cell. Charge the pack fully before first use in a shift environment. After a full charge cycle, the cutout behaviour stops.
Bar indicator showing one fewer bar than expected after inserting a new KNB-45
The TK-3200 uses voltage-threshold logic to drive the bar display — it reads resting pack voltage and maps it to a bar count. A new pack at storage voltage will read lower than a freshly charged one, so the radio shows one or two bars even though the cell is fine. This is not a capacity defect. Put the pack through a full charge cycle in the Kenwood dock until the charge LED goes green, then reinsert. The bar count will reflect actual charge state — typically full bars at 8.2V or above.