Cricket Engage LI3719T42P3h644161 Compatible Battery 3.7V

Cricket Engage — 3.7V Li-ion Replacement Battery (LI3719T42P3h644161)

This is a 3.7V, 1850mAh Li-ion battery for the Cricket Engage smartphone. It replaces OEM part number LI3719T42P3h644161. Fit this battery when the original cell no longer holds a usable charge or shuts the phone down unexpectedly.

• Cricket Engage compatibility: The Engage uses a fixed 3.7V single-cell Li-ion architecture with a direct board connector. This replacement matches that voltage rail and connector pinout, so the phone's charge IC and BMS handshake proceed as normal on first boot.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Engage platform. The BMS accepted the cell without a protection-trip fault, and the charge IC reached full termination voltage without thermal events.
• 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 its coulomb counter against the new cell's discharge curve before high-current charging is introduced to an uncalibrated cell.

Sudden shutdown at 20–30% on the replacement cell

The Engage's fuel gauge IC stores a charge curve calibrated to the original cell. A new cell has a different internal resistance and discharge profile, so the IC misjudges the remaining voltage headroom. Under modem or screen load, the actual cell voltage drops below the BMS cutoff threshold before the reported percentage reaches zero. One full discharge-charge cycle at standard rate forces the coulomb counter to resync to the new cell. After that cycle, the shutdown-at-percentage behaviour resolves.

Phone warm near the battery during the first charge after swap

A new cell comes with slightly elevated internal impedance until it has been cycled once. During that first charge, the charge IC pushes current into a higher-resistance cell, which converts more energy to heat than a broken-in cell would. This is normal and temporary — it does not indicate a fault. If the phone feels uncomfortably hot to the touch rather than slightly warm, disconnect the charger and let the phone cool to room temperature before resuming, then check the charge rate setting.