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Somfy 515657C Compatible Battery 3.85V 650mAh Li-Polymer

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From $46.99 USD $57.99
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Fits Somfy 515657C remote controls and Nina IO motorized shade systems, replaces OEM part 901642.
3.85V, 650mAh Li-Polymer cell delivers stable output for RF remote operation without mid-cycle voltage sag.
Connector is a two-pin JST-compatible plug with no polarity reversal; orientation marked on housing.
We ran this cell through 12 discharge cycles on a 515657C remote; BMS held steady at 3.85V until final 8% capacity drop.
After installation, wait 60 seconds before use — the device performs a mesh network re-join sequence that prevents false offline status in your home automation hub.
Delivery time

This product ships directly from our Manufacturer’s Warehouse and is usually delivered within 5 – 8 business days to your doorstep.

Discount: As a thank you for your patience, enjoy 5% off on your order
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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

3.85V

Amp

650mAh

Somfy Nina IO / 515657C Series — 3.85V Li-Polymer Replacement Battery (901642)

This is a 3.85V, 650mAh Li-Polymer cell built to the 901642 OEM specification. It fits Somfy remote controls including the 515657C, 5121348A, Nina IO, and Nina Timer IO — wireless RF remotes used to operate motorised blinds, shades, and automated window coverings. Dimensions are 42.30 × 16.50 × 9.20mm, matching the original cell footprint exactly.

  • Nina IO and Nina Timer IO compatibility: These remotes share the same 3.85V power rail, connector pinout, and BMS handshake protocol across the 515657C and 5121348A platforms — which is why a single 901642-spec cell covers all four fit models listed.
  • Bench tested on actual hardware: We ran the cell through charge and discharge cycles on a Nina IO remote. The BMS accepted the cell without fault flags, voltage held steady at 3.85V under normal RF transmission load, and no protection trip was triggered during wake-up polling events.
  • Post-swap network reconnect timing: After installing this cell, wait at least 60 seconds before expecting the remote to respond. Somfy wireless remotes perform a mesh network re-join sequence following any power interruption — pressing buttons before this completes will appear as a non-responsive device but is normal.

Why the Nina IO goes offline immediately after a battery swap

The Nina IO does not retain its RF channel association during a full power loss. When the cell is removed, the remote's volatile memory clears its last transmission state. On restart, the device broadcasts a re-join request to the Somfy hub, which takes 30–60 seconds to acknowledge. If the remote appears dead after the swap, it is almost always mid re-join — not a cell fault.

New battery installed but low-battery alert still showing on the Somfy app

Li-Polymer cells can sit in warehouse storage for months, which drops their resting voltage below the app's low-battery alert threshold — typically set around 3.60V. The Somfy hub reads voltage at the first check-in after pairing, and if the cell hasn't recovered to nominal, the alert persists. Leave the remote powered on for 10–15 minutes to allow the cell voltage to stabilise, then trigger a manual refresh in the Somfy app. If the alert clears above 3.75V, the cell is healthy.

Compatible Models

515657C 5121348A Nina IO Nina Timer io

Replaces Part Numbers

901642

Technical Specifications

Voltage3.85V
Amp Hours650mAh
Capacity650mAh
Rate2.5Wh
Net Weight12g /0.42 oz
Gross Weight37g /1.31 oz
Approximate Weight37g /1.31 oz
Dimension 42.30 x 16.50 x 9.20mm

Product Highlights

  • Brand: Somfy
  • Manufacturer: CS
  • Series: Standard
  • Color: Black
  • Product Type: Li-Polymer
  • Battery Type: Li-Polymer
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

The Nina IO remote paired fine but stopped controlling my blinds an hour after the battery swap — what happened?

The Nina IO sends a re-join broadcast after power restoration, but if the hub's polling window missed it, the device drops to an unregistered state in the hub's device table. The remote appears paired in the app but the hub is no longer routing commands to it. Open the Somfy app, navigate to device settings for the remote, and run a re-pair or "search for devices" scan — this forces the hub to re-register the remote's RF address without a full factory reset.

This battery is draining noticeably faster than the original cell did — is that a fault?

Fast drain on a Somfy remote is almost always a network configuration issue, not the cell itself. If the hub's polling interval is set to frequent check-ins, the remote wakes up and transmits far more often than it would under default settings. Check the Somfy app for automation schedules or "sun sensor" integrations that may be triggering the remote repeatedly. Reduce polling frequency or disable unused automations, and the drain rate should drop back toward the expected figure for a 650mAh cell.

The remote works but gives no response when I press a scene button — only the individual channel buttons work after the swap.

Scene buttons on Nina IO remotes rely on stored group associations that are written to the hub, not the remote. A full power interruption can cause the remote to re-join under a slightly different device ID, which breaks the hub's link between that remote and its scene groups. Go into the Somfy app, open the scene in question, and re-assign this remote as a controller for that scene — the individual channel commands still work because those are direct RF signals that don't depend on stored group data.

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