About this replacement
Somfy CL32 Cord Lift — 10.8V Li-ion Replacement Battery (9021217)
This 10.8V, 3400mAh Li-ion battery replaces the original power cell in the Somfy CL32 Cord Lift motorized window treatment system. It also fits the RU 30 Junior, Sonesse 28, and TL25 Cord Lift, along with three additional compatible models. Install it when the existing battery can no longer drive the lift mechanism through a full raise or lower cycle.
- Shared platform across Somfy cord lift models: The CL32, RU 30 Junior, Sonesse 28, and TL25 all run the same 10.8V three-cell Li-ion configuration with a matched connector and BMS handshake. Swapping between these models does not require firmware changes — the protection circuit is uniform across the platform.
- Bench tested on actual hardware: We cycled this cell through repeated lift sequences and monitored the BMS for overcurrent trips during motor start. The protection circuit held stable across load spikes without triggering a false cutoff.
- First-install tip for motorized shades: After fitting the battery, run one full raise-and-lower cycle manually before returning the shade to an automated schedule. This lets the motor controller re-learn the travel limits and prevents a mid-stroke stop on the first automated trigger.
CL32 battery draining faster than the previous cell
A new battery depleting faster than expected is almost always a polling interval issue, not a cell defect. If the Somfy app or connected hub is set to check shade position frequently, the motor controller wakes on every poll and draws current even without moving the shade. Check your automation settings and reduce position-check frequency. Dropping from continuous polling to an event-driven trigger significantly reduces idle draw from the lift electronics.
Low battery alert immediately after fitting a new cell
A new replacement battery shipped in storage state typically sits at 3.5–3.7V per cell — below the threshold that triggers a low-battery alert in the Somfy system. The alert is not a fault with the cell; it clears once the battery charges to its nominal 10.8V operating voltage. Connect the unit to its charging source for a full charge cycle before dismissing the alert. Once voltage climbs above the alert threshold, the system status will update automatically.