Huawei E5330 HB603689EBW Replacement Battery 3.8V 2650mAh

Huawei Speed Wi-Fi NEXT W04 / W05 / HWD35 — 3.8V Li-Polymer Replacement Battery (HB603689EBW)

This is a 3.8V 2650mAh Li-Polymer battery for the Huawei E5330-based hotspots — the HWD35, Speed Wi-Fi NEXT W04, and Speed Wi-Fi NEXT W05. These portable Wi-Fi devices convert mobile signals into wireless networks for multiple connected clients. This replacement fits the original battery bay and matches the OEM part number HB603689EBW.

• HWD35 / W04 / W05 platform fit: All three models run the same Huawei E5330 hardware platform, sharing the same battery footprint, connector pinout, and BMS handshake protocol. Swapping between these models is straightforward — the voltage rail and communication lines are identical across the range.
• Bench tested on actual hardware: We ran this cell under combined modem and Wi-Fi load — simulating peak draw from simultaneous connected clients. The BMS held charge thresholds correctly and did not trip on startup current from the cellular radio.
• Ventilation during extended sessions: Keep the hotspot on an open surface when running long sessions. When client devices are far from the hotspot, the cellular radio pushes to maximum output power. That sustained RF draw concentrates heat at the battery, accelerating cell degradation over time.

Why the HWD35 drops connections when multiple devices are active

The E5330 platform drives both the cellular modem and the Wi-Fi radio from the same battery rail. At maximum client connections, combined current draw spikes sharply. An aged or low-capacity cell cannot hold voltage steady under that combined load, so the BMS trips the output to protect the cell. The result looks like a Wi-Fi dropout but the root cause is voltage sag at the battery, not a signal issue.

Hotspot shows charged but won't boot after sitting unused for weeks

Li-Polymer cells self-discharge during storage. If the HWD35 sits long enough, the battery drops below the minimum boot voltage — typically around 3.0V per cell — and the device will not initialise even after being placed on charge. The charger may show no activity because the BMS blocks input until a recovery pulse re-engages it. Connect the hotspot to a charger and leave it for 20–30 minutes without pressing the power button; the BMS recovery circuit needs uninterrupted voltage before it unlocks the charge path.