WALTON Primo R5 Compatible Battery WMB3000H 3.85V 3000mAh

WALTON Primo R5 — 3.85V Li-Polymer Replacement Battery (WMB3000H)

This is a 3.85V, 3000mAh (11.55Wh) lithium-polymer cell for the WALTON Primo R5 smartphone. It replaces OEM part number WMB3000H when the original cell can no longer hold a usable charge. The physical dimensions are 74.00 × 62.24 × 4.10mm — verify clearance before installing.

• Primo R5 fitment: The Primo R5 uses a 3.85V nominal Li-Polymer cell with a specific connector orientation tied to its charge IC. This replacement matches that voltage rail and connector, so the board recognises the pack and allows charge current to flow.
• Bench tested on actual hardware: We cycled this cell through full discharge and charge on the Primo R5 board. The BMS accepted the pack on first connection, charge current ramped normally, and the protection circuit tripped correctly at the low-voltage cutoff threshold.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-charge cycle at standard rate. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes current into an uncalibrated pack.

Sudden shutdown at 20–30% on the replacement cell

A new Li-Polymer cell has a steeper voltage drop at the bottom of its discharge curve than a worn cell does. The Primo R5's fuel gauge IC is still using the old cell's curve as its reference, so it reads 25% remaining when the actual cell voltage is already near the protection cutoff. Under modem or screen load, voltage collapses fast and the board shuts down before the OS can warn you. Run two full discharge-charge cycles without fast charging — the coulomb counter recalibrates and the shutdowns stop.

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

Li-Polymer cells self-discharge roughly 2–3% per month. If this battery shipped or sat unused for several months, cell voltage may have dropped below 2.5V — the threshold where the BMS locks out to prevent damage. The phone will show no response to the power button and no charge indicator on the screen. Connect the phone to a wall adapter for 20–30 minutes before attempting to power on; this trickle-charges the cell back above the BMS re-enable threshold, typically around 2.8V per cell.