OnePlus 8T+ 5G BLP801 Compatible Battery 7.74V 1800mAh

OnePlus 8T+ 5G (KB2003) — 7.74V Li-Polymer Replacement Battery (BLP801)

This is a 7.74V, 1800mAh Li-Polymer replacement battery for the OnePlus 8T+ 5G smartphone, OEM part number BLP801. It fits the KB2003 model variant and restores power capacity lost through normal cell degradation. Voltage and physical dimensions match the original: 82.30 × 61.80 × 5.50mm.

• 8T+ 5G and KB2003 compatibility: Both designations refer to the same hardware platform sharing the BLP801 connector pinout, cell footprint, and BMS handshake protocol — the battery seats and communicates identically across both.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the KB2003 board. The BMS accepted the cell without fault flags, and the fuel gauge IC began tracking state-of-charge within the first full cycle.
• First-cycle fast charge protocol: On first use after installation, disable Warp Charge for one complete discharge-charge cycle. This lets the fuel gauge IC recalibrate its coulomb counter against the new cell's discharge curve before high-current fast charging pushes into an uncalibrated cell.

Why the OnePlus 8T+ 5G reports wrong battery percentage after a cell swap

The fuel gauge IC on the KB2003 board builds a discharge model from the previous cell's history. After a cell swap, that model no longer matches the new cell's actual voltage-to-capacity curve. The IC reports percentage based on stale data until it recalibrates. One full discharge to system shutdown followed by a full uninterrupted charge to 100% resets the coulomb counter and aligns the gauge to the new cell.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops below the modem or display load threshold before the fuel gauge reads zero — a voltage cliff rather than a true empty cell. The 5G modem on the KB2003 draws sharp current spikes during handoff, pulling cell voltage below 3.0V per cell momentarily even when the gauge shows charge remaining. After two or three full calibration cycles, the fuel gauge learns the real voltage cliff and the shutdowns stop. If they continue past three cycles, check that Warp Charge is re-enabled and confirm the charge IC is not throttling at a fixed 80% cutoff from a settings profile.