About this replacement
Microsoft Surface 1/2 13.5" — 7.5V Li-Polymer Replacement Battery (G3HTA021H)
This 7.5V, 5500mAh (41.25Wh) Li-Polymer battery replaces the original cell in the Microsoft Surface 1 and Surface 2 13.5" tablets. It fits models including the 1703 and 1704 variants. Install it when the existing battery no longer holds charge or fails to power the tablet through normal use.
- Surface 1 and Surface 2 13.5" compatibility: These models share the same 7.5V cell architecture, connector pinout, and BMS handshake across revisions 1703 and 1704. OEM part numbers G3HTA021H, G3HTA023H, G3HTA024H, and G3HTA048H all reference this same physical cell and voltage rail, so one replacement covers the full production run.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a Surface 2 unit. The BMS accepted the handshake cleanly, charge IC communication completed without fault flags, and the tablet reported state of charge without error prompts during the test session.
- Fuel gauge recalibration after swap: After fitting this battery, run the tablet down to automatic shutoff — do not force-shutdown at low percentage — then charge uninterrupted to 100%. This single full cycle lets the fuel gauge IC map its thresholds against the new cell and eliminates the percentage drift that commonly appears right after a battery replacement.
Surface 2 shutting down at 15–25% remaining after battery swap
The Surface 2 shuts down early when the fuel gauge IC still holds voltage-curve data from the old, degraded cell. Under combined display and WiFi load, voltage drops faster than the stale curve predicts, so the BMS triggers a protective cutoff before the reported percentage reaches zero. This is not a fault in the replacement cell — it is a calibration mismatch. Run one full discharge to automatic shutoff followed by an uninterrupted charge to 100%, and the cutoff threshold will realign. After that cycle, the tablet should reach or approach 1% before shutdown.
Surface 2 showing inflated or erratic percentage reading after installation
A new cell has a different internal resistance and charge curve than the worn cell the fuel gauge was calibrated against. Until recalibration, the OS reads the voltage and maps it to the old curve, producing percentage figures that jump, stall, or read higher than actual charge. The fix is mechanical, not software: discharge the tablet fully to automatic shutoff, then charge to 100% without interruption. Once that cycle completes, open Settings and confirm the reading stabilises at a consistent rate during discharge.