TCL Y900 Replacement Battery TLp025A2 3.8V 2500mAh

TCL Y900 / Y710 / S830U — 3.8V Li-Polymer Replacement Battery (TLp025A2)

This is a 3.8V, 2500mAh Li-Polymer cell built to the TLp025A2 specification. It fits the TCL Y900, Y710, S830U, J929L, and six additional compatible models sharing the same battery bay and connector. Voltage and footprint match the factory cell — 73.10 × 54.13 × 4.40mm.

• Y900 / Y710 / S830U platform compatibility: These models share a common battery connector, protection circuit pinout, and BMS handshake protocol. One cell covers all of them without adapter or modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Y900 mainboard. The BMS accepted the new cell, thermal cutoff triggered correctly at ceiling voltage, and the protection circuit tripped cleanly on a simulated over-discharge at 2.5V.
• Fuel gauge recalibration on first use: After installation, disable fast charging and run one complete discharge-to-charge cycle at standard rate. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes current into an uncalibrated coulomb counter.

Sudden shutdown at 20–30% on the TLp025A2 replacement cell

This happens when the fuel gauge IC is still calibrated to the old, degraded cell's voltage curve. The Y900's modem and display pull current spikes that cause the new cell's voltage to sag briefly below the BMS cutoff threshold — even though state-of-charge still reads above 20%. The phone interprets that voltage sag as a dead cell and shuts down. One full discharge cycle at normal screen-on use, down to automatic shutdown, then a full charge resolves it. After that cycle, the coulomb counter recalibrates to the new cell and the false-low cutoff stops.

Phone warm near the battery compartment on the first charge

A fresh TLp025A2 cell has higher internal impedance than a broken-in cell. The charge IC compensates by pushing slightly more voltage to maintain current, which generates heat at the cell surface during the first one or two cycles. This is expected behaviour, not a fault. Warmth should drop noticeably by the second full charge. If the device stays hot past the second cycle, check that the charge IC is not stuck in fast-charge mode — confirm USB-PD negotiation dropped back to 5V standard before continuing.