Sony WI-1000XM2 Replacement Battery 3.8V 290mAh AHB561150

Sony WI-1000XM2 — 3.8V Li-Polymer Replacement Battery (AHB561150)

This is a 3.8V, 290mAh Li-Polymer cell that replaces the AHB561150 inside the Sony WI-1000XM2 wireless earbuds. It powers the right earbud unit, which handles both audio output and the active noise cancellation processor. When the original cell degrades, noise cancellation becomes erratic and wireless connectivity drops before audio cuts entirely.

• WI-1000XM2 right earbud unit: The right housing carries the primary board — it manages Bluetooth, ANC, and codec decoding simultaneously. All three loads share this single 290mAh cell, which is why voltage sag from a degraded battery hits audio quality and ANC together, not independently.
• Bench tested on actual hardware: We cycled this cell under combined Bluetooth and ANC draw. The BMS held the 3.8V nominal rail steady through discharge and triggered low-voltage cutoff cleanly without false trips during noise cancellation peaks.
• ANC calibration after replacement: After fitting this cell, run the Sony Headphones Connect app and re-initialise the noise cancellation optimisation. The ANC processor recalibrates to the new cell's output characteristics — skipping this step leaves noise cancellation running on stale parameters.

Why the WI-1000XM2 drops Bluetooth mid-track on a fresh battery

The right earbud runs Bluetooth radio, ANC, and codec processing from a single cell measuring 52.60 x 10.40 x 5.50mm. When that cell is new but hasn't completed its first full charge cycle, transient current spikes from the ANC chip can momentarily dip voltage below the BMS trip threshold. The radio drops first because it draws the least protection priority. Charge to 100% via the provided cable before first use — the BMS logs the cell's full capacity on that initial cycle and adjusts trip thresholds accordingly.

Earbuds show full charge in the app but ANC cuts out within minutes

This happens when the cell is sitting near storage voltage — typically around 3.6–3.7V — and the app reads the BMS state-of-charge register before it has recalibrated to the new cell. The BMS reports 100% based on voltage alone, but the first real load from the ANC processor exposes the actual usable capacity. Run two full charge and discharge cycles without pausing mid-cycle. After the second cycle, the BMS recalibrates its coulomb counter and the app percentage will track accurately against real remaining charge.