About this replacement
Microsoft Surface Pro 7 — 7.57V Li-Polymer Replacement Battery (G3HTA061H)
This is a 7.57V, 5650mAh (42.77Wh) Li-Polymer battery for the Microsoft Surface Pro 7 and Surface Pro 7 1866. It replaces OEM part number G3HTA061H. The battery slots into the internal bay and connects to the same charge controller and fuel gauge IC as the original cell.
- Surface Pro 7 and 7 1866 compatibility: Both model numbers share the same chassis geometry, connector pinout, and BMS handshake protocol — one cell fits both. The charge IC communicates over the same SMBus line as the factory unit.
- Bench tested on actual hardware: We ran charge and discharge cycles on the Surface Pro 7 platform. The BMS accepted charge handshake on first connection, balanced across cells without fault codes, and held voltage within spec through load transitions from idle to display-on plus active WiFi.
- Fuel gauge recalibration after swap: After installing this battery, run one full discharge to automatic shutoff, then charge uninterrupted to 100%. The fuel gauge IC calibrates its internal model against the new cell's voltage curve — skipping this step causes Windows to report incorrect percentages from day one.
Surface Pro 7 shutting down at 15–25% remaining
The Surface Pro 7 combines a high-resolution display and always-on WiFi on a single power rail. Under combined load, voltage drops sharply below 3.4V per cell — faster than the fuel gauge predicts from resting voltage. The BMS reads this as a low-voltage cutoff condition and shuts down before the reported percentage reaches zero. Running one full calibration cycle after installation gives the fuel gauge accurate data to predict these voltage drops under real load conditions.
Fast charging not available after battery replacement
The Surface Pro 7 uses USB Power Delivery negotiation between the charger and the charge IC on the battery. After a battery swap, the charge IC on the new cell has not yet completed an accepted charge cycle with the system firmware. Until that first full cycle completes, the system defaults to a lower charge rate as a protection measure. Plug in the original Microsoft Surface Connect charger, let the device charge fully without interruption, and USB-PD fast charge negotiation restores on the next connection.