MyPhone MP-S-T 6680 Share Compatible Battery 3.7V 750mAh

MyPhone 6680 Share — 3.7V Li-ion Replacement Battery (MP-S-T)

This is a 3.7V 750mAh Li-ion replacement battery for the MyPhone 6680 Share, 6600, 6600 Free, and 6600 Free XL. Part number MP-S-T matches the OEM cell specification. It restores power to phones with degraded or failed original batteries.

• 6680 Share and 6600 series compatibility: These models share the same battery bay dimensions, connector pinout, and 3.7V nominal voltage rail. The MP-S-T cell fits across all listed variants without modification to the battery contacts or housing.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the 6680 Share platform. The BMS accepted charge from a standard 5V micro-USB source, completed a full cycle without cutoff errors, and held voltage within spec across the discharge curve.
• Fuel gauge recalibration on first cycle: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC recalibrate against the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell — preventing erratic percentage readings from the first day.

Sudden shutdown at 20–30% on the MyPhone 6680 Share

This is a voltage cliff issue, not a capacity defect. When the modem transmits or the screen peaks in brightness, current draw spikes sharply. If the cell's internal resistance is slightly elevated — common in a new cell before the first full cycle — voltage drops below the BMS cutoff threshold even though the fuel gauge still reads 20–30%. One full discharge-charge cycle lowers effective internal resistance and lets the BMS hold voltage through those load spikes. If shutdowns persist after two full cycles, check that the battery contacts are fully seated and free of debris.

OS reports wrong battery percentage after cell swap

The phone's fuel gauge IC stores a discharge curve calibrated to the original cell. A new cell has a different impedance profile, so the coulomb counter miscalculates state-of-charge from the first boot — showing jumps or a percentage that does not match actual remaining capacity. Fix this by running one complete discharge down to automatic shutdown, then charging uninterrupted to 100% without using the phone. After that single cycle, the fuel gauge IC recalibrates its reference points against the new cell. Percentage readings stabilise at 3.7V nominal through the midpoint of the discharge curve.