Meilan U20 Replacement Battery 3.85V 3200mAh Li-Polymer

Meilan U20 / U20 Dual SIM — 3.85V Li-Polymer Replacement Battery

This is a 3.85V, 3200mAh (12.32Wh) Li-Polymer replacement battery for the Meilan U20 and U20 Dual SIM smartphones. It slots into the same battery bay as the original cell and connects to the same flex connector. Capacity figures come from the product data — not estimated from third-party sources.

• U20 and U20 Dual SIM compatibility: Both variants share the same battery bay dimensions, flex connector pinout, and BMS handshake protocol. The 80.50 × 66.70 × 3.40mm cell fits both without modification.
• Bench tested on actual hardware: We ran charge and discharge cycles through the full voltage range and confirmed the BMS communicates correctly with the charge IC — no false full-charge flags, no premature cutoff during discharge.
• Fuel gauge recalibration on first cycle: On first use after installation, disable fast charging and run one complete discharge-charge cycle. This gives the fuel gauge IC a clean reference curve for the new cell before high-current charging begins on an uncalibrated state-of-charge register.

Sudden shutdown at 20–30% on the Meilan U20 after a cell swap

The U20's fuel gauge IC holds a discharge curve learned from the original cell. When a new cell goes in, the stored curve no longer matches actual cell voltage under load. The modem or display pulls current, the new cell's voltage drops faster than the IC predicts, and the phone shuts down before the displayed percentage reaches zero. One full discharge-charge cycle — taken slowly, without fast charging — forces the coulomb counter to relearn the new cell's actual voltage floor and capacity profile.

USB fast charge not activating on the first charge after replacement

On the first cycle, the BMS in a new cell may present higher internal impedance than the charge IC expects. Some proprietary fast-charge handshakes require the charge IC to detect a cell in a specific voltage window before negotiating a higher current rate. If the new cell arrives partially discharged, the IC defaults to standard 5V/1A until it confirms cell voltage has stabilised above roughly 3.6V. Plug in, let the phone charge at standard rate to at least 50%, then disconnect and reconnect — fast charge should activate on the second session.