WD670 ZTE MF673 Replacement Battery 3.8V 2200mAh

ZTE MF673 / WD670 — 3.8V Li-ion Replacement Battery (WD670)

This is a 3.8V, 2200mAh Li-ion battery for the ZTE MF673 portable WiFi hotspot. It fits the MF673 and WD670 devices directly. Capacity matches the original at 2200mAh (8.36Wh).

• MF673 and WD670 fitment: Both the MF673 and WD670 share the same battery bay dimensions, connector pinout, and BMS handshake protocol — that is why one battery covers both models. The voltage rail is 3.8V nominal, and the protection circuit communicates charge state to the hotspot firmware identically across both units.
• Bench tested on actual hardware: We ran this battery on the MF673 with five simultaneous connected clients under a sustained LTE data load. The BMS held the voltage steady above the 3.4V cutoff threshold through the full discharge cycle, and charge termination triggered cleanly at 4.2V with no anomalies.
• Ventilation during extended sessions: Keep the hotspot on an open surface when it is running for long periods. When connected devices are far from the unit, the cellular radio ramps to maximum transmit power — that extra thermal load sits directly against the battery cell and accelerates wear over time.

MF673 dropping connected devices mid-session under full client load

When the MF673 is serving the maximum number of WiFi clients while the modem is handling a high-throughput LTE session, the combined current draw from both the cellular radio and the WiFi chipset spikes sharply. If the battery cell has aged or its internal resistance has risen, voltage sags below the firmware's stability threshold and the hotspot resets the radio stack to protect itself. The result looks like a WiFi dropout but it is actually a voltage event. A fresh cell with low internal resistance eliminates the sag and keeps the session stable.

MF673 not powering on after sitting unused in a drawer

Li-ion cells self-discharge slowly in storage. If the MF673 was left unpowered for several months, the battery may have dropped below the minimum boot voltage — typically around 3.0V — and the BMS will block current to the device as a protection measure. The hotspot will show no response at all, even on charge. Connect it to a 5V USB charger and leave it for 20–30 minutes before attempting to power on; the BMS needs the cell to recover above 3.0V before it will release the output and allow the device to boot.