Asus Transformer Pad TF501T C11P1308 Compatible Battery 3.7V 4050mAh

Asus Transformer Pad TF501T / TF502T — 3.7V Li-Polymer Replacement Battery (C11P1308)

This is a 3.7V, 4050mAh Li-Polymer replacement battery for the Asus Transformer Pad TF501T and TF502T tablets. It matches OEM part numbers C11P1308 and 0B200-00620100. Capacity is rated at 14.99Wh, in line with the original cell specification.

• TF501T and TF502T compatibility: Both tablets share the same battery bay dimensions, connector pinout, and charge IC handshake protocol. The 140.10 × 68.68 × 3.30mm cell fits the chassis without modification, and the BMS communicates with the same fuel gauge IC used across the TF50x platform.
• Bench tested on actual hardware: We ran this battery through charge and discharge cycles on a TF501T unit. The BMS accepted the charge controller handshake without fault codes, held voltage above 3.5V under combined display and Wi-Fi load, and cut off cleanly at the low-voltage threshold.
• Fuel gauge recalibration after installation: After fitting this cell, run the tablet down to automatic shutoff — do not force-power-off — then charge uninterrupted to 100%. This one full cycle resets the fuel gauge IC calibration against the new cell and clears the inaccurate percentage readings that typically appear on first boot after a swap.

Why the TF501T shuts down at 15–25% remaining

The TF501T runs the display backlight and Wi-Fi radio simultaneously under normal use, which creates a combined load spike the fuel gauge IC did not see during calibration on a degraded original cell. When the new cell hits around 3.5V under that load, the BMS interprets the voltage sag as a low-cell condition and triggers a protective shutdown before the percentage counter reaches zero. This is not a fault — it is the BMS doing its job. One full discharge-to-shutoff and uninterrupted recharge cycle recalibrates the fuel gauge against the actual discharge curve of the new cell and resolves the early cutoff.

Fast charging unavailable on the TF501T after battery replacement

The TF501T charge IC re-negotiates its charging profile on the first accepted cycle after a battery swap. Until that cycle completes, the tablet may default to slow-charge mode regardless of which adapter is connected. Connect the original Asus adapter — or a USB-PD adapter rated to at least 18W — and allow one full charge from low to 100% without interruption. After that cycle, the charge IC locks onto the correct profile and fast charging resumes at the expected rate.