Asus PadFone 2 Compatible Battery 3.8V 2050mAh C11-A68

Asus PadFone 2 / A68 — 3.8V Li-Polymer Replacement Battery (C11-A68)

This is a 3.8V, 2050mAh Li-Polymer cell replacing part number C11-A68 in the Asus PadFone 2 smartphone unit. It fits the PadFone 2, PadFone II, and A68 variants — the phone handset that slots into the tablet dock. Dimensions are 62.20 × 55.60 × 4.19mm, matching the original cell footprint inside the chassis.

• PadFone 2 / A68 phone unit compatibility: These three model names — PadFone 2, PadFone II, and A68 — refer to the same 2012 handset. They share the same battery bay geometry, connector orientation, and BMS handshake tied to the C11-A68 part number. One cell covers all three designations.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the A68 platform. The BMS accepted the cell without error flags, charge termination triggered correctly at 4.35V, and the protection circuit tripped at the expected low-voltage cutoff threshold.
• Fuel gauge recalibration on first cycle: After installation, disable fast charging and run one full discharge-to-charge cycle at standard rate. The fuel gauge IC on the PadFone 2 is calibrated to the original cell's discharge curve — skipping this step causes the percentage counter to drift early and trigger premature shutdowns before recalibration completes.

Sudden shutdown at 20–30% on the PadFone 2 after a cell swap

This is a voltage cliff problem, not a capacity problem. When the modem fires during a call or the screen hits peak brightness, instantaneous current draw pulls cell voltage below the BMS cutoff threshold — even though the fuel gauge still shows charge remaining. A fresh cell with an uncalibrated coulomb counter makes this worse because the IC doesn't yet know where the real voltage floor sits. Run one full discharge cycle without fast charging and let the gauge IC map the new cell curve. After that cycle, shutdowns at 20–30% typically stop.

PadFone 2 won't power on after sitting in storage

Li-Polymer cells self-discharge during storage. If the replacement cell shipped at low state-of-charge and sat unused, voltage can drop below 2.5V per cell — the point where the BMS enters lockout to prevent damage. The phone shows nothing: no boot screen, no charge indicator. Connect the original Asus charger and leave it for 20–30 minutes without pressing the power button. The BMS needs trickle current to recover voltage above the lockout threshold before it will pass current to the board. Once the charge LED activates, normal charging can resume.