About this replacement
CAT B15 / B15Q Series — 3.7V Li-ion Replacement Battery (B10-2)
This is a 3.7V, 2000mAh Li-ion cell for the CAT B15 and B15Q rugged smartphones. It replaces OEM part number B10-2 directly. Fit models covered: B15, B15Q, and B15Q AM.
- B15 and B15Q share the same cell format: Both models run the same 3.7V battery rail with identical connector pinout and BMS handshake. The B15Q AM variant uses the same physical cell — no adapter or wiring change needed when swapping between these models.
- Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on a B15 unit. The BMS accepted charge from the native charge IC without fault codes, and the fuel gauge IC tracked cell voltage correctly through both draw phases.
- Fuel gauge recalibration on first install: On first use after installation, disable fast charging and complete one full discharge-charge cycle. This gives the fuel gauge IC a clean reference against the new cell's discharge curve before high-current charging is applied to an uncalibrated cell.
Sudden shutdown at 20–30% on the CAT B15 after a cell swap
The B15's fuel gauge IC holds a discharge curve calibrated to the original cell. A new cell with a different internal resistance profile hits a voltage threshold the gauge wasn't expecting — the phone cuts power to protect the modem and display stack even though charge remains. This is not a fault in the replacement cell. One complete discharge down to automatic shutdown, followed by a full uninterrupted charge, resets the coulomb counter to the new cell's actual curve. After that cycle, the reported percentage tracks real capacity correctly.
Phone warm near the battery during the first charge after replacement
A new high-impedance cell generates more heat during initial charging than a broken-in cell does. The charge IC on the B15 pushes a fixed current profile — on a fresh cell, that current meets higher resistance and converts more energy to heat before the cell's internal structure stabilises. This is normal for the first one to three charge cycles and should reduce noticeably after that. If the case stays hot beyond the third full charge, check that the rear cover is seated correctly — a poorly seated cover traps heat against the cell.