Mechrevo S1 Pro Replacement Battery 11.4V 4400mAh LDW19050065

Mechrevo S1 Pro — 11.4V Li-Polymer Replacement Battery (LDW19050065)

This 11.4V, 4400mAh (50.16Wh) Li-Polymer battery is a direct cell replacement for the Mechrevo S1 Pro laptop. It fits the three-cell pack slot and connects via the original BMS harness. Sourced to match OEM part numbers LDW19050065, SSBS73, and SWIN-GGRTTF01.

• S1 Pro platform fit: The S1 Pro uses a slim 6.40mm pack cavity with a proprietary connector keyed to this cell configuration. Voltage rail, cell count, and BMS handshake all match the original spec — the firmware sees this cell the same way it saw the factory pack.
• Bench tested on actual hardware: We cycled this cell through charge and load on the S1 Pro platform. The BMS accepted the cell without fault codes, thermal throttle stayed inactive throughout, and charge termination triggered correctly at full capacity.
• Post-install calibration on the S1 Pro: After fitting this cell, drain the laptop to hibernate cutoff under normal use — screen on, CPU active — then charge uninterrupted to 100%. This gives the BIOS fuel gauge IC a clean baseline against the new cell and clears the inaccurate health warning that appears after every cell swap.

BIOS reporting battery health as poor after fitting the new cell

The S1 Pro BIOS stores health data in EEPROM tied to the previous cell's cycle history. When a new cell goes in, that stored data no longer matches actual capacity, so the firmware flags it as degraded. This is not a fault with the replacement cell — it is a calibration gap. Running one full discharge-to-hibernate followed by a complete uninterrupted charge resets the learn cycle. After two to three full cycles the health indicator should read accurately.

Laptop shuts down at 20–30% charge shown on the status bar

This happens when the fuel gauge IC has not yet mapped the new cell's voltage curve. The gauge loses track of actual state-of-charge in the lower range, and the cell voltage drops below the BMS cutoff threshold before the displayed percentage reaches zero. It is most visible under CPU and display load together, which pulls more current and accelerates the voltage cliff. Run two full calibration cycles — discharge to hibernate, charge to 100% uninterrupted — and the shutdowns will stop as the gauge locks onto the correct curve. Target a resting voltage of 12.6V at full charge to confirm the cell is healthy.