About this replacement
Microsoft SurfaceBook with Performance Base — 7.6V Li-Polymer Replacement Battery (PBP5)
This 7.6V, 2500mAh Li-Polymer battery replaces the original tablet-portion cell in the Microsoft SurfaceBook with Performance Base. It fits the detachable display unit — not the keyboard base battery. Voltage and capacity match OEM part PBP5 (also cross-referenced as 2ICP5/58/73).
- Tablet cell, not base cell: The SurfaceBook splits power between two batteries — the keyboard Performance Base and the detachable display tablet. This battery powers the tablet half only. Connector pinout and BMS handshake match the tablet's charge controller, not the base unit.
- Bench tested on actual hardware: We cycled this cell through the Surface tablet's charge IC and confirmed the BMS negotiated charge termination correctly at 8.7V peak. The protection circuit tripped as expected at low-voltage cutoff without requiring a manual reset.
- Fuel gauge IC recalibration after swap: After installation, run one full discharge to automatic shutoff, then charge uninterrupted to 100% without interruption. This resets the fuel gauge IC against the new cell's actual capacity curve and resolves the inaccurate percentage readings that almost always appear immediately after a battery replacement.
Why the SurfaceBook tablet shuts down at 15–25% remaining
The Surface tablet's display draws heavily alongside the WiFi and background sync load. At around 15–25% state of charge, cell voltage drops sharply under that combined load — faster than the fuel gauge predicts. The BMS reads this voltage sag as a low-voltage cutoff condition and shuts the system down before the reported percentage reaches zero. Running one full recalibration cycle after installation tightens the fuel gauge model and pushes that cutoff point back toward the correct threshold.
Fast charging not available after battery swap
Surface devices use USB-PD negotiation to authorise higher charge rates. After a battery swap, the charge IC sometimes defaults to a conservative trickle rate until it completes one accepted full charge cycle with the new cell. If the Surface Connect charger is showing slow charge speed post-swap, let the device charge from near-empty to 100% uninterrupted. After that cycle, the charge controller renegotiates and fast charge resumes — no settings change required.