About this replacement
ZTE Z718 / Jasper LTE — 3.8V Li-ion Replacement Battery (Li3820T43P3h604655)
This is a 3.8V, 1900mAh Li-ion battery built to OEM part number Li3820T43P3h604655. It fits the ZTE Z718, Z718TL, Jasper LTE, and Jasper smartphones. Dimensions are 59.53 × 46.18 × 5.42mm — confirm these against your original cell before installing.
- Z718 / Jasper LTE compatibility: The Z718 and Jasper LTE share the same battery bay geometry, connector pinout, and 3.8V nominal rail. One cell fits both variants without modification.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge on a Z718 unit. The BMS accepted charge handshake without error and held voltage above 3.6V through the majority of the discharge curve before dropping to cutoff.
- 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 gives the fuel gauge IC time to map the new cell's discharge curve before high-current charging is applied to an uncalibrated cell.
Sudden shutdown at 20–30% on the Z718 after a cell swap
This is a voltage cliff, not a capacity problem. Under modem transmit or screen-on load, the new cell's internal resistance causes voltage to sag below the BMS cutoff threshold — even when the fuel gauge still reads 20–30%. The fuel gauge IC was calibrated against the old cell's discharge curve and cannot accurately predict the new cell's behaviour until it runs at least one full cycle. After one uninterrupted discharge to auto-off and a full recharge to 100%, the reported percentage and actual cutoff point will align.
Phone shows incorrect battery percentage after replacing the Z718 cell
The coulomb counter and fuel gauge IC on the Z718 retain learned data from the previous cell. When a new cell goes in, that stored discharge model no longer matches the actual cell chemistry and capacity curve. The result is erratic percentage jumps or a reading that stays stuck at one value for extended periods. Drain the battery fully until the phone powers itself off, then charge uninterrupted to 100% — one complete cycle resets the gauge to the new cell's actual curve.