About this replacement
Evolveo StrongPhone X1 — 3.7V Li-ion Replacement Battery (SGP-X1BAT)
This is a 3.7V, 1700mAh Li-ion replacement battery for the Evolveo StrongPhone X1. It uses OEM part number SGP-X1BAT and fits the StrongPhone X1 directly. Cell dimensions are 52.20 × 36.00 × 10.50mm — measure your original before ordering if you are unsure.
- StrongPhone X1 compatibility: The X1 runs a single-cell Li-ion architecture at 3.7V nominal. This replacement matches that voltage rail and connector pinout, so the charge IC and protection circuit communicate with the cell without modification.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the StrongPhone X1 platform. The BMS accepted the cell, charge termination triggered correctly at full capacity, and no overcurrent flags appeared on load.
- Fuel gauge recalibration after swap: On first use, disable fast charging and run one full discharge-to-charge cycle. The fuel gauge IC on the X1 calibrates against the cell's discharge curve — skipping this step with high current into an uncalibrated cell causes erratic percentage readings from the start.
Sudden shutdown at 20–30% on the StrongPhone X1
This happens when the cell voltage drops below what the modem or display can sustain under peak load, even though the fuel gauge still shows charge remaining. Aged cells develop high internal resistance — under load, voltage sags faster than the coulomb counter expects. A replacement cell with lower internal resistance closes that gap. After fitting this battery, run one full discharge cycle so the fuel gauge IC maps the new cell's voltage curve accurately before trusting the percentage readout.
StrongPhone X1 not powering on after storage
If a phone sits in storage for several months with a depleted battery, the BMS can lock the cell out once voltage drops below approximately 2.5V per cell. The phone shows nothing on screen and does not respond to the power button. Connect the phone to a low-current charger — 5V/500mA USB — and leave it for 20 to 30 minutes before attempting to power on. This gives the BMS enough voltage headroom to exit lockout and allow a normal charge cycle to begin.