ZTE MF985 Replacement Battery 3.85V 3000mAh Li-Polymer

ZTE MF985 / MF288 Smart Hub Turbo — 3.85V Li-Polymer Replacement Battery (Li3930T44P4h794659)

This 3.85V, 3000mAh Li-Polymer battery replaces the original Li3930T44P4h794659 cell in the ZTE MF985, MF288, and Smart Hub Turbo portable WiFi hotspot devices. These units share a common battery bay geometry and BMS handshake protocol. Dimensions are 78.85 × 46.04 × 6.20mm — measure your original before fitting if unsure.

• MF985 / MF288 / Smart Hub Turbo fit: All three models use the same connector pinout and BMS communication line. The modem IC queries the battery for state-of-charge data on boot — a mismatched cell causes the device to report incorrect charge levels or refuse to start.
• Bench tested on actual hardware: We ran this cell under combined WiFi radio plus modem load at five concurrent client connections. The BMS held voltage above the 3.4V cutoff floor without triggering a protection trip at sustained draw.
• Cellular signal strength and battery load: In weak signal areas, the MF985 modem runs its transmitter at maximum output power continuously. Park the hotspot near a window or elevated position — this reduces transmit power demand and directly reduces heat buildup at the battery.

Why the MF985 drops all connected clients mid-session under full load

The MF985 runs two high-draw subsystems simultaneously — the LTE modem and the 2.4/5GHz WiFi radio. At maximum client connections, combined current draw spikes sharply. If the battery cell has degraded internal resistance, voltage sags below the BMS protection threshold and the unit cuts power to the radio stack before fully shutting down. The result looks like a WiFi drop rather than a battery fault. A fresh cell with low internal resistance holds voltage through those spikes — check that the replacement seats fully in the connector so contact resistance doesn't add to the problem.

MF985 won't power on after sitting unused for several weeks

Li-Polymer cells self-discharge during storage. If the MF985 sat unused long enough, the cell voltage drops below the minimum boot threshold — typically around 3.0V for this chemistry. The BMS locks out output to protect the cell, and the device shows no response to the power button. Connect the hotspot to its original charger and leave it for 30–45 minutes before attempting to power on — most BMS circuits allow a slow trickle-charge recovery from as low as 2.5V. If the charge LED never illuminates, the cell has discharged below the BMS recovery floor and the battery needs replacement.