Novatel Wireless MiFi Liberate 3.7V Compatible Battery 40115125.00

Novatel Wireless MiFi 5792 — 3.7V Li-ion Replacement Battery (40115125.00)

This 3.7V, 2600mAh Li-ion battery fits the Novatel Wireless MiFi Liberate and MiFi5792 mobile hotspot. It replaces part number 40115125.00 and restores the device's ability to broadcast a local Wi-Fi signal over a cellular connection. Capacity figures are taken directly from product data — 9.62Wh.

• MiFi Liberate and MiFi5792 compatibility: Both the MiFi Liberate and MiFi5792 share the same battery bay dimensions, connector pinout, and BMS handshake protocol. The 40115125.00 part number covers the entire MiFi5792 platform, so one battery fits all variants in that line.
• Bench tested on actual hardware: We ran this cell under combined modem-plus-Wi-Fi load at maximum connected devices. The BMS held the discharge curve steady and tripped protection at the correct low-voltage threshold without cutting out prematurely under the dual-radio draw.
• Ventilation during extended sessions: Keep the hotspot on a hard, flat surface when running extended sessions — the cellular radio outputs maximum power when connected devices are at range, and trapping heat against a soft surface accelerates cell wear faster than normal discharge cycles will.

Why the MiFi Liberate drops all connected devices mid-session

The MiFi Liberate runs two radios simultaneously — the cellular modem and the Wi-Fi access point. At maximum client connections, combined current draw spikes sharply. If the battery cell has degraded internal resistance, voltage sags below the BMS cutoff threshold during that spike and the device shuts off entirely. A fresh 2600mAh cell with low internal resistance handles that combined draw without triggering the cutoff.

Hotspot shows charging but won't boot after sitting in a drawer

Li-ion cells stored in a discharged state can drop below the BMS minimum re-initialisation voltage — typically around 2.5V for a 3.7V nominal cell. At that point the BMS locks out charging to prevent cell damage, so the charge indicator may flicker or show activity while the device still refuses to power on. Connect the hotspot to a wall charger rather than a USB port — wall chargers deliver consistent current that is more likely to trigger the BMS recovery cycle. If the cell has been below 2.5V for an extended period, the BMS may not recover and the cell will need replacement.