TP-Link M7310 Replacement Battery 3.8V 1700mAh TBL-55A1800

TP-Link M7310 ver 1 — 3.8V Li-ion Replacement Battery (TBL-55A1800)

This 3.8V Li-ion battery at 1700mAh (6.46Wh) replaces the original TBL-55A1800 in the TP-Link M7310 ver 1 mobile hotspot. It slots into the same compartment and connects to the same BMS contacts as the factory unit. If your M7310 ver 1 shuts down unexpectedly or no longer holds a charge through a normal session, this is the direct swap.

• M7310 ver 1 fit: The ver 1 revision uses a specific connector pitch and BMS handshake that differs from later M7310 hardware revisions. This cell matches that exact footprint — 62 × 46 × 5.40mm — and communicates correctly with the ver 1 charge controller so the unit reads capacity accurately.
• Bench tested on actual hardware: We cycled this battery under a combined modem and Wi-Fi load simulating multiple connected clients. The BMS held cutoff voltage correctly and did not trigger false low-battery shutdowns during sustained draw.
• Ventilation during extended sessions: Keep the M7310 flat on an open surface when running continuously. The cellular radio ramps to full transmit power when signal is weak, and confined spaces trap that heat directly against the cell, accelerating capacity fade faster than normal cycling would.

Why the M7310 ver 1 drops connected devices mid-session on a new battery

The M7310 ver 1 runs two power-hungry subsystems simultaneously — the LTE modem and the Wi-Fi radio. When multiple clients are active, combined current draw spikes sharply, and a weakened or poorly matched cell sags below the BMS trip threshold momentarily. The unit interprets that sag as a critical low-battery event and cuts power to the Wi-Fi radio to protect the cell. A correctly rated 3.8V cell at 1700mAh maintains the voltage rail above that threshold during these spikes. If drop-outs persist after fitting a new battery, check that the device firmware has not set an artificially high cutoff voltage — a factory reset restores the default 3.4V floor.

M7310 ver 1 not powering on after sitting unused

Li-ion cells self-discharge at roughly 2–3% per month, and the M7310 ver 1 draws a small standby current even when switched off. Left for several months, the battery can drop below 3.0V — the minimum threshold the BMS needs to allow a boot sequence. Pressing the power button produces nothing because the BMS is blocking output, not because the unit is faulty. Connect the original charger and leave it for 20–30 minutes before attempting to power on; most BMS circuits resume normal operation once the cell climbs back above 3.2V. If the device still does not respond after a full charge cycle, check the charge port for debris before assuming the battery is the fault.