I-TEC Smart Window Replacement Battery 3.7V 2600mAh Li-ion

I-TEC Smart Window — 3.7V Li-ion Replacement Battery (ICR18650-1S1P)

This is a 3.7V, 2600mAh Li-ion cylindrical cell replacement for the I-TEC Smart Window. It matches the ICR18650-1S1P specification and slots directly into the Smart Window's battery compartment. The Smart Window uses this cell to power its motor control, sensor polling, and wireless communication functions.

• I-TEC Smart Window compatibility: The Smart Window runs on a single 18650-format cell at 3.7V nominal. This cell matches that voltage rail and the 1S1P configuration — one cell, no series or parallel arrangement. No BMS handshake is required at the cell level; the device manages charge logic internally.
• Bench tested on actual hardware: We cycled this cell through charge and discharge under the load profile typical of a smart home actuator — short motor bursts combined with sustained low-draw wireless activity. The cell held stable voltage throughout and showed no unexpected cutoff behaviour.
• Post-install reconnection window: After fitting this cell, give the Smart Window up to 60 seconds before expecting it to show as online. The device runs a mesh network re-join sequence after any power interruption, and that process completes on its own — no button press needed in most cases.

Smart Window going offline after battery swap

Swapping the cell cuts power completely, which drops the device from the mesh network. When power returns, the Smart Window does not instantly rejoin — it runs an internal boot sequence first, then initiates a network re-join handshake with the hub. This takes up to 60 seconds under normal conditions. If the device is still offline after 90 seconds, check that the hub is powered and within range before assuming a fault with the cell.

Low battery alert showing immediately after fitting a new cell

Cells stored for several months can sit at 3.4V or lower — below the threshold the Smart Window uses to trigger a low battery alert. The device reads cell voltage at boot and flags anything under its set threshold, regardless of whether the cell is new or used. If the alert appears straight after install, charge the cell fully before reinserting it. A fully charged 18650 Li-ion cell should read 4.18–4.20V before fitting.