ZTE C88 Replacement Battery Li3708T42P3h553447 3.7V 800mAh

ZTE C88 / C78 Series — 3.7V Li-ion Replacement Battery (Li3708T42P3h553447)

This is a 3.7V, 800mAh (2.96Wh) Li-ion cell for the ZTE C88, C78, C70, E520, and compatible models. It replaces OEM part numbers Li3708T42P3h553447 and Li3707T42P3h553447. If your original cell has degraded or no longer holds a charge, this is the direct swap.

• C88 / C78 / C70 / E520 platform fitment: These models share the same battery bay dimensions and connector pinout. The BMS handshake protocol and voltage rail are identical across this ZTE budget-tier platform, so one cell covers all listed models.
• Bench tested on actual hardware: We ran this cell through a full charge and discharge cycle on the C88. The BMS accepted the cell without fault codes, and charge termination triggered correctly at 4.2V. No thermal events were observed during the charge cycle.
• 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 recalibrate against the new cell's discharge curve before any high-current charging pushes current into an uncalibrated cell.

Why the C88 reports wrong battery percentage after a cell swap

The fuel gauge IC on the C88 stores a learned discharge curve from the original cell. When a new cell goes in, that stored curve no longer matches the actual cell chemistry and impedance. The phone reads voltage and maps it to the old curve, producing percentage figures that don't reflect real capacity. One full discharge down to auto-shutoff, followed by a full charge to 100%, forces the IC to reset its coulomb counter and re-anchor the curve to the new cell.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops sharply under load — typically during screen-on or a data burst — faster than the fuel gauge predicted. The BMS trips the protection circuit before the display percentage reaches zero. It's a voltage cliff, not a capacity fault. Let the phone shut down naturally, charge it fully to 4.2V, then run one uninterrupted discharge cycle without charging partway through.