Kenwood PB-13 TK-25A Compatible Battery 7.4V 1800mAh

Kenwood TK-25A / TK-28A Series — 7.4V Li-ion Replacement Battery (PB-13)

This is a 7.4V, 1800mAh Li-ion replacement battery for the Kenwood TK-25A, TK-26A, TK-27A, TK-28A, and over 26 additional Kenwood portable two-way radio models. It replaces OEM part numbers PB-13, PB-13H, PB-14, PB-15, PB-17, and PB-18. The pack ships at storage voltage — not flat, not fully charged.

• TK-2x series platform fit: The TK-25A through TK-28A share a common battery bay geometry and 7.4V BMS handshake protocol. All listed OEM part numbers were cross-referenced to this same voltage rail and contact configuration, which is why one replacement covers the full range.
• Bench tested on actual hardware: We cycled this pack through transmit loads on a TK-series dock and confirmed the BMS negotiates correctly at first insertion — no overcurrent trip, no false fault flag. Voltage under PTT load stayed within the radio's accepted operating window.
• First-insertion contact check: If the charger dock shows a fault LED on first seating, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The Kenwood platform requires a clean contact cycle to accept the new BMS handshake before charging begins.

Why the TK-25A cuts out mid-transmission on a freshly inserted battery

The TK-25A draws a sharp current spike the moment PTT is pressed — transmit load is significantly higher than receive or standby draw. If the battery contacts are not fully seated, the BMS reads that spike as an overcurrent event and trips the protection circuit. The radio goes silent, and the pack may feel warm near the contacts. Reseat the battery with firm downward pressure until the latch clicks, then press PTT again — the BMS resets on a clean connection.

Bar indicator showing one fewer bar than expected on a new PB-13

New Li-ion cells ship at roughly 3.6–3.7V per cell to meet transport regulations — that is storage voltage, not full charge. The TK series reads voltage thresholds to display battery bars, so a pack at storage voltage will show one or two bars short of full. This is not a fault with the pack. Run a full charge cycle in the dock first; once the cells reach 4.1–4.2V per cell, the bar indicator will reflect actual capacity.