CCW5000-1 CAT BM1S1B Smartphone Compatible Battery 3.87V 4800mAh

CAT BM1S1B / S75 — 3.87V Li-Polymer Replacement Battery (CCW5000-1)

This 3.87V, 4800mAh Li-Polymer cell replaces the original CCW5000-1 battery in the CAT BM1S1B and S75 smartphones. It matches the OEM voltage rail and physical footprint — 80.00 x 63.80 x 5.00mm — so it seats correctly in the battery bay. Use the capacity figure from this listing: 4800mAh (18.58Wh).

• BM1S1B and S75 compatibility: Both models share the CCW5000-1 form factor, the same flex connector pinout, and the same BMS handshake protocol — that's why one cell covers both SKUs without modification.
• Bench tested on actual hardware: We ran this cell through full charge-discharge cycles on a BM1S1B unit. The BMS accepted the cell without fault flags, and the charge IC reached 4.35V cutoff as expected on the first supervised cycle.
• First-cycle fuel gauge recalibration: 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 fast charging pushes high current into an uncalibrated cell.

Sudden shutdown at 20–30% on the CAT S75 after a cell swap

This happens because the fuel gauge IC is still calibrated to the old cell's voltage curve. The new cell hits a voltage cliff under modem or screen load at a point the gauge hasn't learned yet. The phone sees the voltage drop, interprets it as critically low, and shuts down — even though the reported percentage looks safe. One full discharge-charge cycle at standard rate lets the coulomb counter re-anchor to the new cell and eliminates the premature cutoff.

USB-PD fast charge not triggering on the first cycle after replacement

On the first cycle, the BMS in a new cell may not complete the handshake required for the USB-PD fast charge protocol. The charger falls back to standard 5V charging as a safety measure. This is normal behaviour — the BMS needs one standard charge to initialise. After the first full cycle completes, reconnect the fast charger and confirm the charging icon changes to the fast-charge indicator.