ZTE AB660 Two-Way Radio Replacement Battery 7.4V 2600mAh

ZTE PH660 Series — 7.4V Li-ion Replacement Battery (AB660)

This is a 7.4V, 2600mAh Li-ion replacement for the ZTE AB660 battery pack. It fits the PH660, PH600L, PH600, and PH690 portable two-way radios. The pack uses the same connector and BMS communication protocol as the original, so it seats and charges in the factory dock without modification.

• PH600 and PH690 platform fit: The PH660, PH600L, PH600, and PH690 share the same battery bay geometry, contact pin layout, and 7.4V voltage rail. One pack covers all four models without adapter plates or firmware changes.
• Bench tested on actual hardware: We ran this pack through a full charge cycle in a ZTE dock and cycled PTT transmit loads across the voltage window. The BMS held cutoff cleanly at both the high and low thresholds, with no false overcurrent trips during repeated transmit bursts.
• First insertion into the dock: New packs ship at storage voltage, typically around 3.7V per cell. If the dock LED flashes a fault on first insertion, remove the pack, wipe the gold contact pads with a dry cloth, and reseat firmly. The dock needs a clean contact cycle to read the BMS before it accepts the charge handshake.

Why the PH660 cuts out mid-transmission on a freshly installed battery

PTT transmit on a portable radio draws a sharp current spike — often three to five times the standby draw — in the first 200 milliseconds of keying. If the BMS registers that spike as an overcurrent event, it trips and drops the pack offline instantly. This appears as a hard cutout mid-voice, not a gradual fade. The fix is to press PTT briefly two or three times in quick succession with the radio on but not transmitting audio — this conditions the BMS to the load profile and clears the initial trip threshold. After that, sustained transmission runs cleanly.

Bar indicator showing one fewer bar than expected after fitting the AB660

The PH660 reads voltage thresholds and maps them to bar segments — it does not track charge state any other way. A new pack at storage voltage (around 7.4V resting) sits at the boundary between bar two and bar three on most ZTE firmware versions. This is not a fault with the cell. Charge the pack fully in the dock until the LED goes solid green, then power the radio on — the indicator will show the correct bar level at full charge voltage, typically above 8.2V.