About this replacement
Microsoft Surface CR7 13.5" — 7.4V Li-Polymer Replacement Battery (DAK822470K)
This 7.4V, 2350mAh (17.39Wh) Li-Polymer battery replaces the original cell in the Microsoft Surface CR7 13.5" and Surface Book CR7 series, including CR7-00001, CR7-00002, and CR7-00005. It also fits the extended compatibility list covering eight additional CR7 variants. OEM part numbers DAK822470K, G3HTA020H, G3HTA044H, and G3HTA045H all cross to this cell.
- Surface CR7 series fitment: These models share a common 7.4V two-cell Li-Polymer configuration, an identical flat-pack form factor at 208.10 × 65.60 × 3.30 mm, and the same BMS handshake protocol. Any CR7 variant listed above accepts this battery without connector modification.
- Bench tested on actual hardware: We ran charge and discharge cycles on the Surface CR7 platform and confirmed the BMS accepted the cell without fault codes, voltage regulation stayed within the 7.4V nominal band, and the charge IC completed a full cycle without thermal interrupt.
- Post-install fuel gauge reset: After fitting this battery, run the Surface down to automatic shutoff, then charge uninterrupted to 100% before normal use. The Surface fuel gauge IC calibrates against the old cell's degraded curve — one full cycle resets it against the new cell and clears the inaccurate percentage readings that appear immediately after a swap.
Surface CR7 shutting down at 15–25% remaining
This happens when the display backlight and WiFi radio draw simultaneous current and pull cell voltage below the BMS cutoff threshold before the fuel gauge reaches 0%. The fuel gauge reports a percentage based on charge estimate, but the BMS responds to actual cell voltage. When a degraded or newly installed cell sags under combined load, the BMS trips at a voltage that still reads as 15–25% on screen. One full discharge-to-shutoff cycle followed by an uninterrupted charge to 100% recalibrates the fuel gauge against actual cell voltage, and the premature shutdowns typically stop after that single cycle.
Fast charging not available on the Surface CR7 after a battery swap
The Surface CR7 uses USB-PD negotiation to determine how aggressively the charge IC pushes current into the cell. After a battery replacement, the charge IC treats the new cell as unverified and defaults to a conservative charge rate until it completes one accepted full cycle. This is a firmware-level protection, not a fault. Charge the Surface from 0% to 100% in one uninterrupted session — after that cycle completes, USB-PD negotiation resumes at the normal rate and faster charging becomes available again.