Samsung Galaxy Z Flip F707U Replacement Battery 3.88V 2500mAh

Samsung Galaxy Z Flip F707U — 3.88V Li-Polymer Replacement Battery (EB-BF707ABY)

This 3.88V, 2500mAh Li-Polymer cell is a direct replacement for the Samsung Galaxy Z Flip F707U and Z Flip 5G (SM-F707U1, SM-F707W). It fits the slim foldable chassis and connects to the same BMS handshake points as the original EB-BF707ABY. Capacity listed is 2500mAh — use this figure, not third-party sources.

• Z Flip foldable platform fit: The F707U, SM-F707U1, and SM-F707W share an identical battery bay geometry, connector pinout, and BMS communication protocol — which is why one cell covers all three variants without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Z Flip 5G hardware. The BMS accepted the cell on first connection, thermal cutoff thresholds triggered correctly at upper voltage limits, and the charge IC registered a full 3.88V terminal voltage at completion.
• Fuel gauge recalibration on first cycle: On first use after installation, disable fast charging and run one full discharge-charge cycle at standard rate. This lets the fuel gauge IC map the new cell's discharge curve before the coulomb counter begins reporting accurate state-of-charge data to the OS.

Sudden shutdown at 20–30% on the Z Flip after a cell swap

A new cell has a discharge curve the fuel gauge IC has never seen before. When the phone draws a high current burst — 5G modem handshake or the cover display lighting simultaneously with the main panel — voltage sags below the BMS cutoff threshold before the percentage readout catches up. The phone interprets this as a fault and shuts down, even though the reported figure still shows charge remaining. One full slow discharge-charge cycle recalibrates the coulomb counter so the voltage cliff maps correctly to the percentage scale. After that cycle, the shutdowns stop.

USB-PD fast charge not registering on the first charge after installation

On a freshly installed cell, the BMS may not complete the USB-PD handshake on the first plug-in because the charge IC runs an initial cell-validation sweep at low current before allowing the high-voltage fast-charge contract. This looks like standard 5W charging even with a 25W adapter connected. Unplug, wait 30 seconds, and reconnect — the BMS completes its sweep and the adapter renegotiates to the correct fast-charge profile. If it still defaults to slow charge after two attempts, check that terminal voltage is above 3.0V before plugging in.