Gigabyte gSmart MS800 Compatible Battery XP-13 3.7V 1350mAh

Gigabyte gSmart MS800 Series — 3.7V Li-ion Replacement Battery (XP-13)

This is a 3.7V 1350mAh Li-ion replacement battery for the Gigabyte gSmart MS800, GSmart MS802, GSmart MS820, and g-Smart MW700. OEM part number XP-13. It replaces the original cell when the phone no longer holds adequate charge through a normal day.

• MS800, MS802, MS820, MW700 compatibility: These four models share the same XP-13 cell footprint, connector pinout, and 3.7V nominal voltage rail. The BMS handshake is identical across the series, so the same replacement cell works in all four without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the MS800 platform. The BMS accepted charge from the device's onboard charge IC without overcurrent trips, and the protection circuit cut off correctly at the low-voltage threshold.
• Fuel gauge recalibration on first use: On first use after installation, run one full discharge to auto-off, then charge uninterrupted to 100%. The gSmart's fuel gauge IC calibrates its coulomb counter against the new cell's discharge curve during this cycle. Skipping it leaves the reported percentage unreliable for the first several days.

Sudden shutdown at 20–30% on the gSmart MS800 after a cell swap

A new cell has a slightly different voltage-to-capacity curve than the aged cell the fuel gauge was tracking. When the phone's modem fires a high-current burst — during a call, data sync, or screen wake — the new cell's internal resistance causes a brief voltage dip. The charge IC reads this as a low-voltage event and shuts the phone down even though the displayed percentage looks safe. One full discharge-charge calibration cycle usually eliminates this. If shutdowns persist past the second cycle, check that the battery connector is fully seated — a partial connection raises contact resistance and worsens voltage sag under load.

Phone won't power on after the replacement battery sat in storage

Li-ion cells self-discharge during storage. If the XP-13 cell dropped below approximately 2.5V per cell before installation, the BMS enters a lockout state and blocks normal charging to prevent thermal events on a deeply discharged cell. The phone will show no sign of life when connected to a charger. Connect the phone to a low-current USB source — a laptop port rather than a wall adapter — and leave it for 20–30 minutes. This trickle path lets the BMS confirm the cell is stable before enabling full charge current. Once the screen shows a charging indicator, switch to a wall charger to complete the cycle.