EB-BF724ABY Samsung Galaxy Z Flip 4 Compatible Battery 3.88V 1000mAh

Samsung Galaxy Z Flip 4 — 3.88V Li-Polymer Replacement Battery (EB-BF724ABY)

This 3.88V, 1000mAh Li-Polymer cell replaces the internal battery in the Samsung Galaxy Z Flip 4 (SM-F721U, SM-F721U1, SM-F721W, and related variants). It matches OEM part numbers EB-BF724ABY and GH82-29433A. Capacity is 1000mAh (3.88Wh), identical to the original cell specification.

• Z Flip 4 foldable form factor: The SM-F721 series uses a split-cell layout inside a hinged chassis. This cell fits the inner battery position — same footprint at 56.00 x 25.00 x 4.80mm — and communicates with the device's fuel gauge IC over the same BMS handshake protocol as the OEM unit.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on Z Flip 4 hardware. The BMS accepted the cell without error flags on the first connection. Charge current stepped correctly through trickle, CC, and CV phases.
• Fuel gauge recalibration after cell swap: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle. This gives the fuel gauge IC one full pass to recalibrate its coulomb counter against the new cell's discharge curve before high-current charging begins.

Why the Z Flip 4 reports wrong battery percentage after a cell swap

The Z Flip 4 uses a coulomb-counting fuel gauge IC that builds a discharge model against the original cell over hundreds of cycles. When a new cell goes in, that learned model no longer matches the actual cell chemistry. The gauge reads a stored curve, not the real cell state, so percentage readouts can be off by 10–20% until recalibration occurs. One full discharge to automatic power-off, followed by a full charge to 100%, resets the IC's reference points and restores accurate reporting.

Sudden shutdown at 20–30% on a replacement cell

This happens when the modem, display, or processor pulls a short burst of high current that the cell voltage cannot sustain under load. At roughly 20–30% state of charge, cell voltage drops below the BMS cutoff threshold under that transient load — the phone shuts off even though the gauge still shows charge remaining. The fuel gauge IC's stored model has not yet mapped the new cell's actual voltage-capacity curve at that range. Running the recalibration cycle described above — one full discharge and full recharge with fast charge disabled — typically eliminates these shutdowns by aligning the cutoff threshold to the correct voltage point on this cell.