Huawei E5573S-852 Compatible Battery 3.8V 4500mAh

Huawei E5573S / E5787P Series — 3.8V Li-ion Replacement Battery (HBC04666RDW)

This is a 3.8V 4500mAh Li-ion battery for the Huawei E5573S-852, E5573S-853, E5573S-856, and E5787P mobile hotspot devices. It replaces OEM part HBC04666RDW and restores full power capacity to the portable WiFi hotspot. Capacity is 4500mAh (17.1Wh) — taken directly from product specification.

• E5573S and E5787P platform compatibility: These models share the same battery bay dimensions (65.35 × 46.00 × 12.30mm), 3.8V nominal voltage rail, and BMS communication protocol. The connector pinout and charge termination handshake are identical across the series, so one battery cell works across all listed variants.
• Bench tested on actual hardware: We ran this battery through charge and discharge cycles on the E5573S platform. The BMS accepted full charge without error flags, voltage held steady under simultaneous 4G modem and WiFi radio load, and the protection circuit tripped correctly at the low-voltage cutoff threshold.
• Ventilation during extended hotspot sessions: Keep the hotspot on a hard flat surface with airflow around it during long sessions. When connected devices are at range limit, the cellular radio locks to maximum transmit power — sustained heat from the radio transfers directly into the battery cell and accelerates wear over time.

Why the E5573S drops connected devices mid-session under full load

When the hotspot is running at its maximum client count, the combined draw from the 4G modem and the WiFi radio spikes well above idle current. An ageing or undercharged battery cannot sustain the voltage rail under that combined load, so the BMS briefly cuts output to protect the cell. This registers as a momentary disconnection for all users. A fully charged, capacity-correct replacement battery maintains the voltage headroom needed to absorb those load spikes without triggering the cutoff.

Hotspot shows battery icon but won't boot after weeks in a drawer

Li-ion cells self-discharge during storage — roughly 1–2% per week at room temperature. If the hotspot sat unused long enough, the cell voltage drops below the minimum boot threshold (typically around 3.0V for a 3.8V nominal cell), and the device will not initialise even with the charger connected. Connect the charger and leave it for at least 20–30 minutes before attempting to power on — the BMS needs to see voltage recover above the boot floor before it will release the power rail to the processor.