Lenovo Pad Pro 2021 L20B2P31 Replacement Battery 3.85V 8400mAh

Lenovo Pad Pro 2021 (TB-J706F / TB-J716F) — 3.85V Li-Polymer Replacement Battery (L20B2P31)

This 3.85V, 8400mAh (32.34Wh) Li-Polymer battery replaces the original cell in the Lenovo Pad Pro 2021 tablet. It fits the TB-J706F and TB-J716F board variants. Install this when the existing cell no longer holds a usable charge or causes unexpected shutdowns.

• TB-J706F and TB-J716F compatibility: Both board variants share the same battery connector, voltage rail, and BMS handshake protocol. The L20B2P31 OEM part number covers the full production run, while L20C2P31 through L20X2P31 are regional and revision-specific part numbers for the same physical cell.
• Bench tested on actual hardware: We ran charge and discharge cycles through a TB-J716F unit. The BMS accepted the cell without fault flags, charge IC stepped through trickle, CC, and CV phases cleanly, and cutoff voltage held at 4.35V with no thermal events during the CV tail.
• Fuel gauge recalibration after install: After fitting this cell, run the tablet down to automatic shutoff — do not force-stop at any percentage — then charge uninterrupted to 100%. This lets the fuel gauge IC map its reference curve to the new cell and clears the incorrect percentage readings that appear immediately after a swap.

Pad Pro 2021 shutting down at 15–25% battery remaining

The Snapdragon 870 driving the 2K display plus active WiFi pulls a combined load spike that the degraded original cell cannot sustain. When cell voltage drops below roughly 3.6V under that load, the BMS trips the cutoff before the OS gauge reaches zero — so the tablet shuts off while still showing charge. A fresh cell holds voltage under the same spike without triggering the cutoff threshold. After installing this battery, run the recalibration cycle described above so the gauge IC learns where the new cell's voltage cliff actually sits.

Fast charging not resuming after battery replacement

Lenovo's proprietary fast-charge protocol on the Pad Pro 2021 requires the charge IC to complete at least one accepted full charge cycle before it enables the higher current path. If you connect a fast charger immediately after install and see only a standard 5W charge rate, this is expected behaviour — it is not a fault with the battery or charger. Let the first full charge cycle complete at whatever rate the IC allows. On the second connection, the fast-charge handshake negotiates correctly and the higher rate resumes. Confirm with the USB-PD indicator in Lenovo's battery settings once the cycle finishes.