Ailunce HD1 Replacement Battery FA9140A 7.4V 3000mAh

Ailunce HD1 — 7.4V Li-ion Replacement Battery (FA9140A)

This 7.4V 3000mAh Li-ion battery replaces the FA9140A pack on the Ailunce HD1 dual-band handheld transceiver. It fits the HD1's battery bay directly and mates with the charging dock and radio body contacts without modification. Capacity is 3000mAh (22.2Wh), matching the original specification.

• HD1 platform fit: The HD1 runs a 7.4V nominal rail across both VHF and UHF transmit paths. This pack uses the same cell configuration and BMS output profile as the FA9140A, so the radio's voltage monitoring circuit sees a familiar handshake and doesn't flag a fault on power-up.
• Bench tested on actual hardware: We ran this pack through transmit-cycle loading on the HD1 bench unit. The BMS held stable under the current spike at PTT press and did not trigger overcurrent cutoff during sustained dual-band TX bursts.
• First insertion into the HD1 dock: If the dock shows a fault LED on first insertion, remove the pack and wipe the gold contact strip with a dry cloth before reseating. A new BMS at storage voltage sometimes needs a clean contact cycle before the dock accepts the handshake and begins charging.

Why the HD1 cuts out mid-transmission on a new FA9140A pack

New Li-ion cells ship at storage voltage — typically 3.6–3.7V per cell, not full charge. When the HD1 fires a transmit burst, current draw spikes sharply. If the pack hasn't been charged first, the BMS sees the voltage dip fall outside its safe window and trips the overcurrent protection, dropping the radio mid-transmission. This isn't a fault in the pack — it's the BMS doing its job on an uncharged cell. Charge the FA9140A fully before the first transmission cycle; a rested, fully charged cell holds the voltage rail above the BMS cutoff threshold even at peak TX draw.

Bar indicator showing one fewer bar than expected after fitting this pack

The HD1 uses a voltage-threshold bar display — it reads battery state by measuring terminal voltage against fixed reference points, not a fuel gauge chip. A new pack at storage voltage reads low on those thresholds, so the display shows one or two bars even when the cell is healthy. After a full charge cycle, terminal voltage rises above the upper reference threshold and the display corrects itself. If the bar count still reads low after a confirmed full charge, check that the contact strip is clean and making solid connection — a resistive contact causes a voltage drop that the radio interprets as a depleted cell.