Samsung Galaxy Tab 7.7 Replacement Battery SP397281A 3.7V 5000mAh

Samsung Galaxy Tab 7.7 / P6800 — 3.7V Li-Polymer Replacement Battery (SP397281A)

This is a 3.7V 5000mAh Li-Polymer replacement battery for the Samsung Galaxy Tab 7.7, covering model numbers P6800, GT-P6810, and SCH-I815. It slots into the original battery bay and connects to the same BMS communication pins as the factory cell. Use the Capacity figure from the product listing — 5000mAh — as the authoritative spec.

• P6800 / GT-P6810 / SCH-I815 compatibility: These variants share the same physical cell bay, connector pinout, and BMS handshake protocol. SP397281A and SP397281P are OEM cross-references for the same cell configuration — the 1S2P notation on SP397281P refers to the internal pack arrangement, not a different voltage rail.
• Bench tested on actual hardware: We ran this cell on a P6800 unit and monitored BMS communication through charge and discharge cycles. The protection circuit engaged at the correct low-voltage threshold and accepted a full charge without triggering over-current cutoff.
• Fuel gauge recalibration after swap: After fitting this battery, run the tablet down to automatic shutoff — do not manually power it off — then charge uninterrupted to 100%. This single full cycle forces the fuel gauge IC to recalibrate against the new cell's actual capacity curve and clears the inaccurate percentage readings that commonly appear after a battery swap.

Why the Galaxy Tab 7.7 shuts down at 15–25% remaining

The Tab 7.7 combines display backlight and WiFi antenna draw during active use, which creates a combined load spike that can pull cell voltage below the BMS protection threshold faster than the fuel gauge predicts. The gauge was calibrated to the original cell's voltage-versus-capacity curve, so it reads 20% while the actual cell voltage has already dropped to the cutoff point. This is more pronounced on an aged or freshly swapped cell. Run one full discharge-to-shutoff and uninterrupted charge-to-100% cycle to re-anchor the gauge to the new cell.

Fast charging unavailable after battery replacement on the GT-P6810

Samsung's proprietary charge negotiation on the Tab 7.7 series requires the charge IC to complete at least one accepted full cycle before it unlocks higher charge rates. Immediately after a swap, the controller defaults to standard 5V input until it has verified the new cell's response profile. This is a firmware-level handshake, not a hardware fault. Charge the tablet fully from near-empty once using the original Samsung adapter, and the faster charge rate will be available on subsequent cycles.