ZTE AR910 Replacement Battery Li3727T42P3h665678 3.7V 2900mAh

ZTE AR910 Series — 3.7V Li-ion Replacement Battery (Li3727T42P3h665678)

This 3.7V, 2900mAh Li-ion battery replaces the OEM cell in the ZTE AR910, AR910-A, and AR910-B portable WiFi hotspot. It matches the original connector pinout and BMS handshake, so the device recognises the pack and reports charge level correctly. Dimensions are 65.90 × 55.45 × 7.85mm — verify these against your existing cell before fitting.

• AR910, AR910-A, AR910-B compatibility: All three variants share the same battery bay, connector, and 3.7V power rail. The BMS on each model uses the same authentication protocol, so one cell works across the range without modification.
• Bench tested on actual hardware: We ran this pack under simultaneous modem and WiFi radio load — the BMS held voltage at the rated 3.7V nominal and cut off cleanly at the low-voltage threshold without triggering a mid-session shutdown.
• Ventilation during extended hotspot sessions: When the AR910 is connecting devices at maximum range, the cellular radio runs at full transmit power. Keep the hotspot on a hard, flat surface with airflow underneath — trapping heat against the battery accelerates cell wear faster than normal charge cycling does.

Why the AR910 drops connected devices mid-session under heavy load

The AR910 runs two radios simultaneously — the cellular modem and the WiFi access point. At maximum connections, combined current draw spikes sharply, which can pull cell voltage below the BMS protection threshold for a fraction of a second. The BMS interprets this as a fault and cuts output, dropping every connected device. A worn cell with higher internal resistance makes this worse because voltage sag is proportionally greater. A fresh cell with lower internal resistance reduces the sag amplitude and keeps the BMS from tripping.

AR910 shows full charge but shuts off within minutes of unplugging

This is cell memory corruption from shallow cycling — the BMS has lost accurate track of actual capacity and reports 100% against a much smaller usable window. The fix is a full discharge to the device's automatic cutoff, then a complete charge to 4.2V without interruption. If the original cell still does this after two full cycles, the cell has degraded past recovery and replacement is the correct next step.