About this replacement
HP Pro Slate 12 — 3.8V Li-Polymer Replacement Battery (HSTNH-C412D-SD)
This is a 3.8V, 9500mAh (36.1Wh) Li-Polymer battery for the HP Pro Slate 12 tablet. It replaces part numbers HSTNH-C412D-SD, DN02, 780783-0C1, 782644-005, 799168-001, 780731-2C1, and HSTNH-C412D. Fits models K7X87AA, K7X87AA#ABA, and K7X88AA.
- Pro Slate 12 platform fit: HP's Pro Slate 12 uses a single flat Li-Polymer cell matched to a 3.8V charge rail and a proprietary BMS connector. Every part number listed above references the same electrical spec and the same physical footprint — 216.38 × 136.45 × 2.68mm — so the fit is confirmed across all K7X87AA and K7X88AA variants.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the Pro Slate 12 platform. The BMS handshake initialised correctly on first connection, charge current ramped normally, and the protection circuit tripped at the expected low-voltage threshold without requiring a manual reset.
- Fuel gauge recalibration after swap: After installing this battery, run one full discharge to automatic shutoff, then charge uninterrupted to 100% without using the tablet. This forces the fuel gauge IC to map its charge curve against the new cell and clears the inaccurate percentage readings that almost always appear immediately after a battery replacement.
Why the Pro Slate 12 shuts down at 15–25% remaining
The Pro Slate 12 pulls simultaneous load from a large IPS display and active WiFi — two of the highest-draw components in any tablet. When battery voltage sags under that combined load, it can cross the BMS cutoff threshold while the fuel gauge still reads 15–25%. The old cell's degraded internal resistance makes this worse over time, but a new cell with an uncalibrated gauge can trigger the same symptom. One full discharge-to-shutoff cycle followed by an uninterrupted full charge resets the gauge reference and eliminates most false shutdowns.
Fast charging not available after battery swap
If the Pro Slate 12 reverts to standard charge speed after a battery replacement, the USB-PD negotiation cycle is the likely cause. The tablet's charge IC sometimes requires one completed charge cycle before it re-enables the higher-current profile with a new cell. Plug into the original HP charger, let the tablet charge fully without interruption, then unplug and repeat — the second cycle typically restores normal charge rate. If fast charge still does not return, confirm the charger output meets the tablet's USB-PD voltage and wattage spec before swapping any other components.