USCellular MWP3505 Replacement Battery 3.8V 1950mAh Li-ion

USCellular MWP3505 / Render — 3.8V Li-ion Replacement Battery

This 3.8V, 1950mAh (7.41Wh) Li-ion cell fits the USCellular MWP3505, MWP3505US, and Render smartphones. It replaces a degraded or failed original battery without replacing the handset. Voltage and form factor match the stock cell exactly — 56.00 x 55.50 x 5.00mm.

• MWP3505, MWP3505US, and Render compatibility: All three variants share the same 3.8V power rail, connector pinout, and BMS handshake protocol — one cell covers the full lineup without adapters or modifications.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the MWP3505 platform. The BMS accepted the new cell without fault flags, and the charge IC completed a full cycle without thermal or current errors.
• Fuel gauge recalibration on first use: After installation, disable fast charging and run one complete discharge-to-charge cycle at standard rate. This lets the fuel gauge IC map the new cell's discharge curve before it begins tracking percentage — skipping this step causes percentage jumps and early shutdown flags.

Sudden shutdown at 20–30% on the MWP3505 after a cell swap

The MWP3505's fuel gauge IC retains the discharge curve from the old, degraded cell. When the new cell is installed, the IC misreads the voltage-capacity relationship and calls a low-voltage cutoff earlier than the true state of charge. The modem radio and display draw spike current at that point, pulling the cell voltage below the BMS floor momentarily — triggering a hard shutdown. One full uncalibrated discharge-charge cycle at standard current corrects the IC's curve and stops these early cutoffs.

USB fast charge not activating on the replacement cell's first cycle

On first connection after a swap, the charge IC on the Render and MWP3505 runs a trickle pre-charge phase to verify cell health before stepping up to fast-charge current. A new cell at full voltage can confuse this handshake — the IC stays in pre-charge mode and the phone never signals fast charging. Disconnect the cable, power the phone off, reconnect, and let the IC re-enter its detection sequence from a cold start. If the issue persists after one full standard-rate cycle, verify the charge voltage is reaching 4.35V at the termination point.