Microsoft Surface 3 10.8" G3HTA003H Replacement Battery 3.78V 7200mAh

Microsoft Surface 3 10.8" — 3.78V Li-Polymer Replacement Battery (G3HTA003H)

This is a 3.78V, 7200mAh (27.22Wh) Li-Polymer replacement battery for the Microsoft Surface 3 10.8-inch tablet. It fits the Surface 3 1645 and MSK-1645 variants and replaces OEM part numbers G3HTA003H, G3HTA004H, and G3HTA007H. If your Surface 3 no longer holds a charge or shuts down unexpectedly, this cell replaces the degraded original.

• Surface 3 1645 and MSK-1645 compatibility: These variants share the same 3.78V battery rail, physical footprint (204.60 × 95.26 × 3.20mm), and BMS connector pinout. All three OEM part numbers reference the same cell configuration — G3HTA003H, G3HTA004H, and G3HTA007H are interchangeable across those board revisions.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Surface 3 platform. The BMS handshake completed without fault flags, charge IC accepted the cell without thermal events, and the tablet held the charge state correctly across sleep cycles.
• Fuel gauge recalibration after swap: After fitting this battery, run the tablet down to automatic shutoff, then charge uninterrupted to 100% without using the device. This forces the fuel gauge IC to recalibrate against the new cell's actual charge curve and corrects the inaccurate percentage readings that commonly appear straight after a replacement.

Surface 3 shutting down at 15–25% battery remaining

This happens because the fuel gauge IC was calibrated to the old, degraded cell. Its voltage-to-capacity curve no longer matches the new cell, so the tablet hits the low-voltage cutoff threshold earlier than the displayed percentage suggests. When the display and WiFi draw simultaneously, the voltage sag is sharp enough to trip the protection circuit even at nominally safe percentages. One full discharge-to-shutoff cycle followed by an uninterrupted charge to 100% resets that calibration and eliminates the premature shutdown.

Fast charging not resuming after battery replacement on Surface 3

The Surface 3 uses USB-PD negotiation to determine whether to apply the higher charge rate. After a battery swap, the charge IC on the new cell needs at least one accepted full charge cycle before the firmware re-enables the elevated current profile. If fast charging appears absent, connect the original Microsoft charger — third-party adapters that don't fully negotiate USB-PD will not trigger it. Complete one full charge to 100% with the Microsoft charger and the fast charge rate will resume on subsequent cycles.