About this replacement
Sony Tablet S (SGPBP04) — 3.7V Li-Polymer Replacement Battery
This is a 3.7V, 6000mAh lithium-polymer battery for the Sony Tablet S. It fits the GPT121 and SGPT121US/S hardware platforms alongside the Tablet S. Capacity figures come from the product data — 6000mAh, 22.2Wh.
- Tablet S platform fit: The GPT121 and SGPT121US/S variants share the same battery bay dimensions, connector pin-out, and charge-management circuit as the base Tablet S. One battery cell covers the full platform without modification.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the Tablet S platform. The onboard battery management system accepted the new cell, completed a full charge cycle without fault flags, and the charge IC reported correct voltage at rest.
- Fuel gauge reset after installation: After fitting the new cell, run the tablet down to automatic shutoff, then charge it uninterrupted to 100% without using the device. This single full cycle resets the fuel gauge IC calibration against the new cell and clears the inaccurate percentage readings that commonly appear after a swap.
Sony Tablet S shutting down between 15% and 25% remaining
This is a voltage-cliff failure. Under combined load — backlight at full, WiFi active, background sync running — the cell voltage drops faster than the fuel gauge expects. The system hits the low-voltage cutoff threshold before the displayed percentage reaches zero. The fuel gauge IC is still calibrated to the old, degraded cell curve. One full discharge-to-shutoff followed by an uninterrupted charge to 100% remaps the gauge to the new cell. After that cycle, the percentage display tracks the actual cell state accurately.
Battery percentage jumping or reading incorrectly after the swap
The fuel gauge IC stores a charge profile from the previous cell. When a new cell is installed, the stored profile no longer matches the actual voltage curve, so the displayed percentage drifts or jumps. This is a calibration mismatch — not a fault in the new cell. Discharge the tablet fully until it powers off on its own, then charge it to 100% without interruption. The IC re-learns the new cell's voltage curve and the percentage stabilises at that point.