CAT B100 Replacement Battery CB-115 3.7V 1200mAh Li-ion

CAT B100 — 3.7V Li-ion Replacement Battery (CB-115)

This is a 3.7V, 1200mAh Li-ion battery for the CAT B100 rugged smartphone. It replaces OEM part CB-115 directly. Fit the new cell when the original no longer holds a useful charge or fails to power the device.

• CAT B100 fitment: The B100 uses a 3.7V single-cell Li-ion circuit with a proprietary connector footprint matched by CB-115. The BMS handshake runs over the same three-pin contact arrangement as the factory cell, so the phone's charge IC recognises the replacement without any configuration change.
• Bench tested on actual hardware: We cycled this cell through the B100's charge IC and confirmed BMS communication throughout. The protection circuit tripped correctly at both high-current draw and low-voltage cutoff — no false positives on the modem radio load spike.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging if available and run one full discharge-charge cycle before normal use. This gives the fuel gauge IC one complete pass to map the new cell's discharge curve before the coulomb counter locks in its reference points.

Why the B100 reports wrong battery percentage after a cell swap

The B100's fuel gauge IC builds its percentage model by tracking coulombs in and out of the original cell over many cycles. When you fit a new cell, that learned curve no longer matches the new cell's actual voltage-to-capacity relationship. The IC keeps using the old reference, so it reports percentages that don't reflect real charge state. One full discharge down to auto-off followed by a full uninterrupted charge resets the reference and brings the readout back in line.

Sudden shutdown at 20–30% on the replacement cell

This happens when the fuel gauge IC hasn't recalibrated and the cell hits its actual voltage floor before the displayed percentage reaches zero. Under modem or screen load, the cell voltage sags below the BMS cutoff threshold — typically 3.0V — while the OS still shows charge remaining. The phone shuts off to protect the cell, not because of a fault in the replacement. Run one full cycle to completion and the shutdowns stop; the gauge will then track the real voltage cliff accurately.