Autec Air A4 Crane Remote Compatible Battery BH3V7L 3.7V

Autec Air A4 / A6 / A8 — 3.7V Li-Polymer Replacement Battery (BH3V7L)

This 3.7V, 1200mAh lithium-polymer battery replaces the OEM BH3V7L cell in Autec Air A4, Air A6, and Air A8 wireless crane remote controls. It fits the same slim 62 × 39 × 6mm footprint as the factory cell and connects to the same BMS circuit inside the remote. Capacity is 4.44Wh — identical to spec.

• Air A4, A6, and A8 compatibility: All three remotes share the same battery bay dimensions, 3.7V supply rail, and BMS handshake protocol. One cell fits all three without modification or adapter.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on an Air A4 remote. The BMS accepted the cell immediately, balanced charge terminated correctly at 4.2V, and protection circuits tripped at the expected undervoltage threshold without error codes.
• Storage charge for infrequent crane use: Crane remotes often sit unused for weeks between jobs. If the cell drops below 2.5V, the BMS enters deep-discharge lockout — the remote will not power on and a standard charger may not recover it. Charge this battery once a month during idle periods to keep cell voltage above 3.0V.

Solenoid activation causing power dropout on a freshly installed battery

When the Autec Air remote sends a crane command, the solenoid or relay in the receiver draws a short inrush current spike. If the battery cell is at storage voltage — around 3.6V — internal resistance is higher than at full charge, and the voltage can sag enough to trigger the BMS overcurrent cutoff. The remote drops out mid-command, which looks like a faulty battery when the actual cause is a cell that was never fully charged before use. Charge the replacement cell to 4.2V before the first operation. A full charge lowers internal resistance and keeps voltage stable through inrush events.

Remote showing low-battery indicator immediately after swap

Replacement Li-Polymer cells ship at storage voltage — typically 3.6V to 3.7V — not at full charge. The Autec Air firmware reads cell voltage to calculate state of charge, so a cell sitting at 3.65V will display as partially or critically low the moment the remote boots. This is not a defective battery. Connect the remote to its charger and bring the cell to 4.2V before reading the battery indicator. Once fully charged, the display will read correctly.