About this replacement
Huawei E5372T / E5377 Series — 3.7V Li-ion Replacement Battery (HB5F3H)
The HB5F3H is a 3.7V, 3400mAh Li-ion battery for the Huawei E5372T, E5377, E5775, and GL06P mobile hotspot devices. These portable WiFi routers share the same battery bay dimensions and connector, so one part fits the entire platform. Capacity is drawn from product data: 3400mAh / 12.58Wh.
- E5372T / E5377 platform compatibility: These models run the same Balong modem chipset and use an identical BMS handshake protocol. The battery management circuit expects the same charge termination voltage across all variants, so this cell seats and communicates correctly without firmware conflict.
- Bench tested on actual hardware: We ran this battery on an E5372T with eight simultaneous client connections. The BMS held charge termination at 4.2V and did not trigger low-voltage cutoff during combined modem and WiFi radio draw at full load.
- Cellular signal and battery load: In areas with weak LTE signal, the E5372T's radio module ramps to maximum transmit power. Keep the hotspot in a ventilated spot during long sessions — heat buildup at sustained high-power radio output accelerates cell wear faster than anything else this device does.
Why the E5372T drops all connected clients mid-session
The E5372T runs two high-draw subsystems simultaneously: the LTE modem and the dual-band WiFi radio. When battery cell impedance rises — common in aged cells — voltage sags sharply under this combined load. The BMS interprets the voltage dip as a critical low event and shuts the output rail before the display even shows a low-battery warning. A new cell with lower internal resistance holds voltage stable under peak draw and prevents the BMS from tripping incorrectly.
E5372T showing full charge but powering off immediately after removing cable
This happens when a cell has been stored fully discharged for several months. The cell voltage drops below 2.5V and the BMS blocks charge current to protect against lithium plating — the device shows a charge animation off the cable but the cell never recovers enough to sustain load. To attempt recovery, connect the charger and leave it for 45–60 minutes before pressing power. If the device still shuts off instantly when unplugged, the cell is below recovery threshold and needs replacement. A healthy replacement cell will read above 3.6V before first boot.