UMX Unimax U693CL Compatible Battery 3.8V 2250mAh Li-Po

UMX Unimax U693CL / U683CL — 3.8V Li-Polymer Replacement Battery (ChinoBATT01 / UBT2300)

This 3.8V, 2250mAh (8.55Wh) lithium-polymer cell replaces the factory battery in the UMX Unimax U693CL and U683CL smartphones. It fits when the original cell no longer holds a charge, drops out under load, or refuses to power the device on at all. Dimensions are 65.80 × 58.10 × 4.50mm — confirm clearance before installing.

• U693CL and U683CL platform fit: Both models share the same battery bay dimensions, connector pinout, and charge management IC handshake, so one cell covers both. The BMS communicates with the phone's fuel gauge over the same protocol on each variant.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the U693CL, confirming the BMS handshake completes correctly and charge termination triggers at the expected voltage without error flags from the system.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one full discharge-to-charge cycle at standard rate. The fuel gauge IC on this phone calibrates its coulomb counter against the cell's actual discharge curve — skipping this step causes the percentage readout to drift or report incorrectly for the first several cycles.

Sudden shutdown at 20–30% on the U693CL after a cell swap

This happens because the fuel gauge IC is still using the discharge curve from the old, degraded cell. The new cell has a steeper voltage cliff under modem and screen load than the IC expects, so it reads 25% but the terminal voltage drops below the cutoff threshold mid-use. The fix is one full uninterrupted discharge cycle — drain the phone until it shuts itself off, then charge to 100% without interruption. After that cycle, the coulomb counter resets its reference and the shutdowns stop.

Phone shows correct percentage but the number jumps erratically between readings

Erratic percentage jumps — 47% one moment, 61% the next — point to the fuel gauge IC recalibrating against a cell it hasn't characterised yet. The IC on the U693CL uses a learned model of the cell's internal resistance; a new cell has lower impedance than a worn one, which throws off the voltage-to-capacity mapping. Run two complete discharge-charge cycles at standard charge rate with the screen active during discharge to give the IC real load data. After the second cycle, readings stabilise to within a few percent per reading.