About this replacement
Huawei 601HW / 603HW — 3.8V Li-ion Replacement Battery (HWBCK1)
This is a 3.8V, 2400mAh Li-ion battery for the Huawei 601HW and 603HW mobile hotspot devices. It replaces OEM part number HWBCK1. When the original cell degrades and the hotspot no longer holds a session, this is the direct swap.
- 601HW and 603HW platform fit: Both models share the same battery bay dimensions, connector pinout, and BMS handshake protocol. The cell footprint is 65.40 × 46.08 × 6.10mm — a tight tolerance that matters, because even a fractional mismatch prevents the battery door from seating and breaks BMS communication.
- Bench tested on actual hardware: We ran this cell under simultaneous WiFi client load and active LTE data transfer. The BMS held steady through connect/disconnect cycles without triggering an overcurrent cutoff — the failure mode we see most often with off-spec cells in hotspot hardware.
- Ventilation during extended sessions: Keep the 601HW on an open surface when running long sessions. When connected devices are far from the hotspot, the cellular radio runs at maximum transmit power. That heat load accumulates in the battery, and the BMS will throttle or cut out if the cell temperature climbs past its upper threshold.
Why the 601HW drops connected devices mid-session under full load
The 601HW runs both a cellular modem and a WiFi radio from the same 3.8V cell. At maximum client connections, combined current draw spikes sharply — especially when the LTE signal is weak and the modem increases transmit power to compensate. A degraded or undersized cell will sag below the BMS's minimum voltage threshold during these spikes, triggering a protection cutoff that drops all connected clients. Replacing the cell with one that meets the original 2400mAh rating restores the headroom the BMS needs to ride through those peaks without cutting out.
Hotspot shows charging but won't boot after sitting unused
If the 601HW was stored flat for several months, the battery may have self-discharged below the minimum boot voltage — typically around 3.0V for this cell chemistry. At that point the device draws power from the charger but the BMS blocks the boot sequence until the cell recovers to a safe level. Leave it on charge for 30–45 minutes without pressing the power button; the BMS re-initialises once the cell climbs back above 3.2V. If the device still won't boot after a full hour on charge, confirm the charger is delivering 5V DC before assuming the battery is faulty.