About this replacement
Kenwood P25 / TK-5230 / TK-5330 / TK-5430 — 7.4V Li-ion Replacement Battery (KNB-L1)
This 7.4V, 5000mAh (37Wh) lithium-ion battery replaces the KNB-L1, KNB-L2, KNB-L3, KNB-N4, and related OEM packs. It fits the Kenwood P25 series and TK-5230, TK-5330, and TK-5430 portable radios. These are land mobile radios used in professional and commercial environments where losing comms mid-shift is not an option.
- TK-5000 and P25 platform fit: The TK-5230, TK-5330, and TK-5430 share the same battery bay geometry, contact pin layout, and 7.4V power rail. The BMS in this pack is matched to that voltage range, so the radio firmware accepts the handshake without throwing a fault code.
- Bench tested on actual hardware: We ran this pack through a full charge cycle on a Kenwood multi-unit charger dock and monitored BMS communication. The protection circuit tripped correctly at the low-voltage threshold and the dock advanced to the ready state without fault LEDs.
- First-insertion contact check: If the charger dock shows a fault LED on first insertion, remove the battery, 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 begins — this is not a defect.
Why the TK-5430 cuts out mid-transmission on a new KNB-L1 replacement
P25 radios draw a sharp current spike the moment PTT is pressed — RF output on the TK-5430 can pull over 2A in the first milliseconds of transmission. If the replacement pack arrived at storage voltage (typically around 3.7V per cell, or ~7.4V total), the BMS may interpret that transmit surge as an overcurrent event and cut power briefly. This is not a faulty battery — it is the protection circuit doing its job on an undercharged cell. Charge the pack fully before the first transmit test; at full charge the cells handle the PTT spike without tripping.
Bar indicator showing one fewer bar than expected after fitting this pack
Kenwood P25 radios use simple voltage-threshold bar indicators — each bar maps to a voltage band, not a fuel gauge percentage. A new pack shipped at storage voltage will sit in a lower voltage band and display one fewer bar than a fully charged pack. This is normal cell behaviour, not a capacity problem. Put the battery through one full charge cycle on the Kenwood dock and the indicator will reflect the correct charge state. Expect the first bar to appear around 7.2V and the full display at or above 8.0V.