Sharp 550SH Replacement Battery 3.7V 950mAh Li-ion

Sharp 550SH / GX-E30 Series — 3.7V Li-ion Replacement Battery (XN-1BT30)

This is a 3.7V, 950mAh Li-ion replacement battery for the Sharp 550SH, GX-E30, GX-F200, GX-L15, and compatible models. It replaces OEM parts XN-1BT30 and CE-BL150. Fit this when the original cell shows capacity fade, fails to hold a charge, or the phone shuts down unexpectedly under load.

• Multi-model fit — 550SH and GX series: These models share the same battery bay dimensions, connector pinout, and BMS handshake voltage. The 59.80 × 35.63 × 4.50mm cell slots into all listed variants without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on compatible hardware. The BMS responded correctly to charge termination, held steady at 3.7V nominal, and showed no thermal irregularities during the constant-current phase.
• Fuel gauge recalibration on first use: On first installation, disable fast charging and run one full discharge-to-charge cycle. This lets the phone's fuel gauge IC map its coulomb counter to the new cell's actual discharge curve before high-current charging begins on an uncalibrated cell.

Why the 550SH reports wrong battery percentage after a cell swap

The fuel gauge IC in the 550SH stores a discharge curve calibrated to the original cell. When you fit a new cell, the IC does not automatically reset — it continues using the old curve. This causes the percentage to appear stuck, jump suddenly, or read 100% when the cell is not fully charged. One complete slow discharge followed by a full charge cycle forces the IC to relearn the new cell's voltage-to-capacity relationship.

Sudden shutdown at 20–30% on a freshly installed cell

This happens when the fuel gauge IC has not yet recalibrated and the phone hits a voltage cliff under screen or modem load. The cell voltage drops sharply below the protection threshold — typically around 3.0V — before the percentage display catches up. The phone cuts out to protect the cell, even though the displayed percentage looks safe. Run one full uninterrupted discharge cycle to recalibrate, and check that the cutoff voltage stabilises at 3.0V or above during normal use.