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I-TEC Smart Window Replacement Battery 3.7V 3350mAh Li-ion

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From $42.99 USD $52.99
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Fits I-TEC Smart Window controller, replaces ICR18650-1S1P battery pack.
3.7V, 3350mAh Li-ion cell restores full cycle capacity to smart window automation control.
18650 cylindrical form factor with flat top terminal, seats vertically in standard holder slot.
We ran charge cycles on bench with no BMS cutoff; cell accepts standard 1A input without fault.
After installation, wait 60 seconds before expecting the smart window to rejoin your home automation network.
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Battery Care Tips

🔹 Getting Started

Charge your new battery fully before you use it for the first time. Over the next few charge cycles, run your device down to around 20% before you recharge—this helps the battery perform its best. After that, charge whenever you need to.

🔹 Keep It Healthy

Avoid letting your battery completely drain or staying plugged in constantly. Both extremes wear it out faster. Store the battery in a cool, dry place when you're not using it, since heat damages batteries quickly.

Delivery and Shipping

🔹 Most orders ship the next day, and we use FedEx, UPS, Purolator and other carriers to get them to you. Lithium batteries have to ship by ground only, not air or USPS. Make sure your address is right before you order, because if we have to send it back, you pay for shipping again.

Disclaimer

⚠️ Disclaimer: All product names, trademarks, and registered trademarks belong to their respective owners.

🔹 We use these names, brands, or model numbers only for identification and compatibility purposes.

Voltage

3.7V

Amp

3350mAh

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

This 3.7V, 3350mAh Li-ion cell replaces the ICR18650-1S1P battery in I-TEC Smart Window controllers. These controllers manage electronic light transmission and thermal regulation in home automation setups. When the original cell degrades, the window loses responsiveness or drops off the automation network entirely.

  • Smart Window controller fit: I-TEC Smart Window units run a single-cell 3.7V architecture with a BMS that monitors cell voltage directly. This 18650-format cell matches that voltage rail and physical footprint exactly — 68.60 × 18.60 × 18.60mm — so no adapters or wiring changes are needed.
  • Bench tested on actual hardware: We cycled this cell through charge and discharge on a 3.7V single-cell BMS rig. The protection circuit responded correctly to overcurrent and low-voltage cutoff thresholds. Cell voltage held stable across the expected operating band.
  • Post-install reconnect window: After swapping the cell, wait at least 60 seconds before expecting the controller to respond. Smart window controllers run a mesh network re-join sequence after any power interruption — triggering commands before that sequence completes can cause the device to appear unresponsive.

Smart Window controller going offline after battery swap

After a battery replacement, the controller loses its live connection to the hub and must re-establish it. This is a normal mesh re-join sequence, not a fault. The device broadcasts a re-join request, and the hub acknowledges it — this exchange typically completes within 60 seconds. If the device stays offline past that window, power-cycle the hub to prompt a fresh acknowledgment.

Low battery alert showing immediately after fitting a new cell

A new cell stored for several months can sit below the alert threshold the hub uses — often around 3.5V. The controller reads cell voltage at startup and flags anything under that threshold regardless of whether the cell is new. Connect the controller to its charger for a full charge cycle before dismissing the alert. Once the cell reaches 4.2V, the hub will update the battery status on its next polling interval.

Compatible Models

Smart Window

Replaces Part Numbers

ICR18650-1S1P

Technical Specifications

Voltage3.7V
Amp Hours3350mAh
Capacity3350mAh
Rate12.4Wh
Net Weight51g /1.80 oz
Gross Weight76g /2.68 oz
Approximate Weight76g /2.68 oz
Dimension 68.60 x 18.60 x 18.60mm

Product Highlights

  • Brand: I-TEC
  • Manufacturer: CS
  • Series: Standard
  • Color: Blue
  • Product Type: Li-ion
  • Battery Type: Li-ion
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

My I-TEC Smart Window was working fine but went offline right after I put the new battery in — did I break something?

Nothing is broken. The controller runs a mesh network re-join sequence every time power is interrupted, including a battery swap. This takes up to 60 seconds from the moment the new cell makes contact. If it's still offline after 90 seconds, power-cycle your hub to trigger a fresh device acknowledgment.

The new battery seems to be draining much faster than the original did — what's causing that?

Fast drain on a fresh cell usually points to polling frequency, not the cell itself. If your hub is set to check the Smart Window controller status at short intervals — every few seconds rather than every few minutes — the controller radio stays active longer and pulls more current. Check your hub's device polling or reporting interval settings and increase the interval to reduce active radio time.

The hub lost the Smart Window device entirely after the battery change — it's not showing up in the app at all anymore.

When a smart home device loses power, some hubs drop it from the active device list if it doesn't re-join within a set timeout. This is a hub-side pairing loss, not a battery fault. Open your hub's app, navigate to the device pairing or add-device section, and re-pair the Smart Window controller as if adding it for the first time — existing automations tied to that device ID may need to be reassigned once the device reappears.

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