Sony BT22 Replacement Battery 3.7V 350mAh 65358-01

Sony BT22 / DR-BT22 Series — 3.7V Li-Polymer Replacement Battery (65358-01)

This is a 3.7V, 350mAh Li-Polymer replacement cell for the Sony BT22 and DR-BT22 series Bluetooth wireless headsets. It fits the BT22, DR-BT22, DR-BT22G, and DR-BT22IK models. It replaces OEM part numbers 65358-01, 64399-01, and 64327-01.

• BT22 and DR-BT22 series compatibility: These models share the same 3.7V cell format, connector pinout, and BMS handshake protocol — the base station communicates with the cell to track charge state, so all variants in this range accept the same physical and electrical spec.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the BT22 platform. The BMS accepted the pack without error flags, held the 3.7V nominal rail cleanly, and the protection circuit responded correctly at both high-charge and low-voltage cutoff thresholds.
• First-cycle conditioning on the base station: On first use, seat the headset in its base and run a complete charge cycle before taking a call. The DR-BT22 base logs the new cell during this cycle — until it does, the talk-time indicator on the base will not read accurately.

Base station not recognising the new pack or showing a charging error

The DR-BT22 base uses a BMS handshake to identify the battery before committing to a charge cycle. If the new cell arrives at storage voltage — typically around 3.6V — the base may flag a fault or refuse to start charging on first dock. This is not a defective battery. Remove the headset, wait ten seconds, and re-seat it firmly so the contacts are flush. If the fault light persists, try a different power outlet; some base units are sensitive to USB power supplies that drop below rated output under load. One full seated charge cycle clears the handshake flag in most cases.

Headset cutting out mid-call on a fresh battery

The BT22 draws power simultaneously from the audio circuit and the DECT radio during a call. That combined load creates brief current spikes that can trip the BMS low-voltage protection on a cell that has not yet been conditioned. The cutout clears when you re-seat the headset in the base for a few minutes, because the cell voltage recovers above the BMS cutoff threshold — typically 3.0V. Run three to five full charge and discharge cycles through the base station and the mid-call cutouts will stop as the cell stabilises under that dual draw.