G3HTA001H Microsoft Surface Book Keyboard Compatible Battery 7.59V

Microsoft Surface Book 1785 Keyboard — 7.59V Li-Polymer Replacement Battery (G3HTA001H)

This is a 7.59V, 8900mAh (67.55Wh) Li-Polymer battery for the detachable keyboard base of the Microsoft Surface Book 1785. It replaces OEM part G3HTA001H. The keyboard base draws from this cell to power the secondary battery system, additional USB ports, and wireless input functions when the screen is docked.

• Surface Book 1785 keyboard base fit: The 1785 keyboard base uses a dedicated battery separate from the clipboard screen unit. Both communicate charge state through the hinge connector. This cell matches the connector pinout, BMS handshake protocol, and physical dimensions (293.00 × 116.76 × 5.50mm) required for that docking interface.
• Bench tested on actual hardware: We cycled this cell through the Surface Book docking and undocking sequence under combined keyboard, USB, and display-pass-through load. The BMS responded correctly to charge negotiation from the clipboard unit and held voltage within the expected 7.59V nominal range without tripping protection circuits.
• Fuel gauge reset after installation: After fitting this battery, run the keyboard base down to automatic shutoff, then charge uninterrupted to 100% before use. The fuel gauge IC calibrates against the new cell during that first full cycle and corrects the inaccurate percentage readings that appear immediately after a swap.

Why the Surface Book keyboard base reports a different charge percentage than the clipboard screen

The Surface Book runs two separate fuel gauge ICs — one in the clipboard screen, one in the keyboard base. After a keyboard battery swap, the base gauge is calibrated to a cell with different internal resistance characteristics than the original. Windows aggregates both readings and can display totals that look inconsistent. The base gauge needs one full discharge and charge cycle to map its state-of-charge curve to the new cell. Until that cycle completes, the percentage shown in Windows Battery settings may read 10–15% higher or lower than actual capacity.

Surface Book keyboard base shutting off at 15–25% remaining

This happens when the fuel gauge IC still holds calibration data from the degraded original cell. The old cell had a steep voltage cliff at low charge — the gauge was tuned to cut off at that point. A fresh cell has a flatter discharge curve, but the gauge triggers the same early shutoff voltage threshold before the new cell is actually depleted. Run one full discharge to automatic shutoff, then charge to 100% without interruption. That cycle rewrites the gauge's end-of-discharge voltage reference to match the new cell's curve.