Green Orange M2S Replacement Battery 3.7V 1500mAh Q802

Green Orange M2S / Mars 2S — 3.7V Li-ion Replacement Battery (Q802)

This is a 3.7V 1500mAh Li-ion cell for the Green Orange M2S, S2, and Mars 2S smartphones. It replaces the original Q802 battery when capacity has dropped or the cell has failed entirely. Dimensions are 59.20 × 45.90 × 5.15 mm — confirm these against your existing cell before installing.

• M2S / S2 / Mars 2S platform fit: These models share the same battery bay geometry, connector pinout, and 3.7V nominal voltage rail, which is why a single Q802 cell covers all three variants.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the M2S platform. The BMS accepted charge handshake without rejection, and cell voltage held stable through full discharge without premature cutoff.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell.

Sudden shutdown at 20–30% on the replacement cell

This happens because the fuel gauge IC is still running the discharge curve from the old, degraded cell. The new cell has a steeper voltage cliff under modem and screen load than the IC expects, so it reads 25% right up until the cell drops below the cutoff threshold. The fix is one full uninterrupted discharge-charge cycle with the phone in normal use — no top-ups mid-cycle. After that cycle, the coulomb counter resets against the actual cell curve and percentage reporting stabilises.

Phone feels warm near the battery during the first charge

A new high-impedance cell produces more heat than a broken-in cell during the initial charge cycle. The charge IC on the M2S is pushing current into a cell with higher internal resistance than it will have after a few cycles, so the extra energy dissipates as heat. This is normal for the first one or two charges and not a sign of a fault. If warmth continues past the third full charge cycle, check that the charging port is not delivering voltage above 5V.