About this replacement
Asus Transformer AiO P1801 — 3.7V Li-Polymer Replacement Battery (C11-P1801)
This is a 3.7V, 5130mAh lithium-polymer battery for the Asus Transformer AiO tablet. It fits the P1801 and P1801-B037K models. Install it when the original cell no longer holds a charge or shuts the tablet down unexpectedly.
- P1801 series compatibility: The P1801 and P1801-B037K share the same battery bay, connector pinout, and BMS handshake protocol — one cell covers the full range without modification.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a P1801 unit. The BMS accepted the new cell without fault codes, and charge current stepped down correctly as the cell approached full capacity.
- Fuel gauge reset after installation: After fitting this battery, run the tablet down to automatic shutoff, then charge it uninterrupted to 100%. This forces the fuel gauge IC to recalibrate against the new cell's actual capacity curve and clears the inaccurate percentage readings that commonly appear after a swap.
Transformer AiO shutting down at 15–25% battery remaining
The P1801's display and wireless components draw combined load spikes that exceed what a degraded — or freshly installed, uncalibrated — cell can deliver without hitting the BMS low-voltage cutoff. The BMS reads the voltage cliff as an empty cell and triggers shutdown even though the percentage indicator hasn't reached zero. This is a fuel gauge calibration issue, not a cell defect. Run one full discharge-to-shutoff cycle followed by an uninterrupted charge to 100%, and the shutdowns will stop once the gauge IC maps the new cell's discharge curve.
Fast charging unavailable on the Transformer AiO after a battery swap
After a battery replacement, the charge IC sometimes defaults to a conservative charge profile until it completes one full accepted cycle with the new cell. This appears as slow charging even on a charger that previously delivered faster rates. It is not a fault with the replacement cell or the charger. Complete one full charge from near-empty to 100% without interruption, and the charge IC will resume normal charge current on subsequent cycles.