Li3928T44P4h735350 ZTE Avid Trio Compatible Battery 3.85V 2800mAh

ZTE Avid Trio / Z833 — 3.85V Li-ion Replacement Battery (Li3928T44P4h735350)

This is a 3.85V, 2800mAh Li-ion battery for the ZTE Avid Trio, Z833, Q802T, and ZFIVE 2 smartphones. It replaces the original Li3928T44P4h735350 cell when capacity loss causes the phone to shut down early or charge inconsistently. Voltage and capacity match the OEM specification exactly.

• Z833 and Q802T platform fit: These models share the same battery bay dimensions, connector pinout, and charge IC handshake. The BMS communicates over the same thermistor line, so the fuel gauge IC accepts the new cell without throwing a hardware fault.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on a Z833 unit. The charge IC accepted the cell on the first connection, BMS protection tripped correctly at low-voltage cutoff, and no anomalous heat was recorded at the connector.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell, preventing early percentage jumps.

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

The Avid Trio's fuel gauge IC holds the discharge curve of the old, degraded cell in memory. When the phone hits a load spike — modem transmitting, screen at full brightness — the new cell's actual voltage curve doesn't match what the IC expects, so it misreads remaining capacity. The phone reaches its low-voltage cutoff threshold while the display still shows 20–30%. One full uninterrupted discharge down to automatic shutdown, followed by a full charge to 100%, forces the coulomb counter to relearn the new cell's curve. After that cycle, reported percentage tracks real charge state accurately.

Phone won't power on after the replacement battery sat in storage

Li-ion cells self-discharge during storage. If the cell drops below approximately 2.5V, the BMS enters lockout mode and blocks all charge current as a safety measure. Connect the phone to a wall charger — not a PC USB port — and leave it undisturbed for 15–20 minutes without pressing the power button. The charge IC trickle-charges the cell up to the BMS re-enable threshold, which sits around 2.9V, at which point normal charging resumes and the phone powers on.