About this replacement
Samsung Galaxy S4 / GT-I9500 — 3.7V Li-ion Replacement Battery (B600BE)
This is a 3.7V, 2100mAh Li-ion replacement battery for the Samsung Galaxy S4 and Galaxy S4 LTE. It fits GT-I9500, GT-I9502, and over 33 related variants using the B600BE cell format. Drop this in when the original cell has degraded past the point where the phone holds a usable charge through a normal day.
- GT-I9500 / GT-I9502 cell compatibility: These variants share the same battery bay dimensions, connector pinout, and BMS handshake protocol. The B600BE format covers the full S4 line because Samsung held that spec consistent across LTE and dual-SIM hardware revisions.
- Bench tested on actual hardware: We ran this cell in a GT-I9500 and monitored BMS communication through the full charge cycle. The protection circuit accepted the charge IC handshake on the first connection, and the cell held voltage through a full discharge without tripping the low-voltage cutoff prematurely.
- Fuel gauge recalibration on first use: On first installation, disable fast charging and run one complete discharge-to-charge cycle at standard rate. The Galaxy S4 fuel gauge IC recalibrates its coulomb counter against the new cell's discharge curve during this cycle — skipping it causes the percentage readout to drift immediately after installation.
Why the Galaxy S4 reports wrong battery percentage after a cell swap
The Galaxy S4 uses a coulomb-counting fuel gauge IC that builds its charge model against the discharge curve of the original cell. When a new cell goes in, the IC still references its stored curve, which no longer matches the new cell's chemistry profile. The result is percentage readings that lag, jump, or plateau at values that don't reflect actual charge state. One full discharge below 5% followed by a slow charge to 100% forces the IC to remap against the new cell. After that cycle, percentage accuracy stabilises.
Sudden shutdown at 20–30% on the replacement cell
This is a voltage cliff issue, not a capacity fault. Under high-load conditions — modem handoff, screen at full brightness, or GPS active — the cell briefly can't sustain voltage above the system's cutoff threshold, and the phone shuts down even though the fuel gauge still shows charge remaining. The underlying cause is the fuel gauge IC operating on a miscalibrated curve, so it never issued an accurate low-voltage warning. Complete the recalibration cycle first. If shutdowns persist after one full discharge-charge cycle, check that cell voltage at shutdown reads above 3.4V before swapping again.