OnePlus 6T BLP685 Compatible Battery 3.85V 3600mAh

OnePlus 6T / A6010 / A6013 — 3.85V Li-Polymer Replacement Battery (BLP685)

This is a 3600mAh Li-Polymer cell at 3.85V, built to the BLP685 specification. It fits the OnePlus 6T across all regional variants — A6010 and A6013. The battery powers every function of the phone: processor, display, modem, and sensors.

• A6010 and A6013 compatibility: Both variants share the same battery bay dimensions, connector pinout, and BMS handshake protocol. The BLP685 cell addresses all three — same 73.82 × 60.66 × 4.65mm footprint, same flex connector, same thermistor line.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a 6T unit. The BMS accepted the cell without fault flags, fast-charge negotiation completed on the second cycle, and the fuel gauge IC tracked state-of-charge without erratic jumps after one full calibration cycle.
• First-cycle fuel gauge reset: After installation, disable Warp Charge and run one full discharge down to automatic shutdown, then charge to 100% on standard charging. The OnePlus fuel gauge IC recalibrates its coulomb counter against the new cell's discharge curve during that first cycle — skip this and the percentage readout will drift.

Why the 6T reports wrong battery percentage after a cell swap

The OnePlus 6T uses a coulomb-counting fuel gauge IC that builds its charge model from the original cell's discharge curve. When a new cell goes in, the IC still references the old curve — so the percentage shown on screen doesn't match the actual charge in the new cell. This mismatch produces readings that appear stuck, jump suddenly, or show 100% with no reserve left. One complete discharge-to-shutdown followed by a full standard charge corrects the model and locks the gauge to the new cell's actual behaviour.

Sudden shutdown at 20–30% remaining on a fresh BLP685 cell

This happens when the modem or display draws a high current spike and the cell voltage drops below the BMS cutoff threshold — even though the gauge still shows charge remaining. It's a voltage-cliff issue, not a capacity issue: the fuel gauge IC hasn't yet mapped where the new cell's voltage drops steeply under load. Run the first-cycle calibration described above, and verify the shutdown stops occurring below 15%. If shutdown continues after calibration, check that the flex connector is fully seated — a loose contact raises internal resistance and accelerates voltage sag under load.