Sprint Zing Replacement Battery 3.7V 1800mAh Li-ion

Sprint Zing / AirCard 753S / AirCard 754S — 3.7V Li-ion Replacement Battery

This 3.7V 1800mAh Li-ion battery replaces the original cell in the Sprint Zing mobile hotspot and the Sierra Wireless AirCard 753S and 754S. All three share the same battery bay, connector, and BMS communication protocol. Capacity figure is 1800mAh as specified in product data.

• Zing, 753S, and 754S compatibility: These three hotspot models use the same physical form factor — 61.30 × 41.30 × 6.60mm — the same connector pinout, and the same BMS handshake over the data line. One battery fits all three without modification.
• Bench tested on actual hardware: We ran this cell in a Zing under a five-device Wi-Fi load with simultaneous LTE data transfer. The BMS held the charge threshold correctly, cut off at low-voltage floor, and accepted a full recharge cycle without error codes on the device display.
• Ventilation during active sessions: Keep the hotspot on a hard, flat surface — not a couch cushion or pocket — during long sessions. The cellular radio runs at maximum output when connected devices are far away or in weak signal areas, and trapped heat shortens cell life faster than charge cycles do.

Hotspot disconnecting users mid-session on a new battery

The Zing runs two power-hungry systems simultaneously — an LTE modem and a Wi-Fi radio. At maximum connected devices, the combined draw creates short voltage sag spikes that the BMS can misread as a low-battery event, triggering a brief shutdown. This is more common when cellular signal is weak, because the modem boosts transmit power automatically. Reducing active connected devices from the maximum to three or four usually eliminates the sag. If the issue persists, check that the battery contacts in the bay are clean and making full contact.

Zing won't power on after sitting unused for several weeks

Li-ion cells self-discharge during storage, and the Zing's BMS requires a minimum voltage — around 3.0V — before it will allow the device to boot. If the battery has dropped below that threshold, the hotspot appears completely dead and won't respond to the power button. Plug into a wall charger, not a USB port, and leave it for at least 20–30 minutes before attempting to power on. If the charge indicator light doesn't appear within five minutes of connecting the charger, the battery has likely dropped into deep discharge and needs a longer recovery charge at low current before the BMS re-initialises.