About this replacement
Somfy SGS / GDK / SGA / SLD Series — 9.6V Ni-MH Replacement Battery (2 400 720)
This 9.6V 2000mAh Ni-MH battery replaces part number 2 400 720 across Somfy SGS, GDK, SGA, SLD, and compatible models in the same series. It powers motorized blinds, shutters, and awnings that rely on this cell to execute travel commands from the Somfy hub or remote. Voltage and capacity match the original specification exactly.
- SGS, GDK, SGA, SLD platform fit: These models share the same 9.6V battery rail, connector pinout, and BMS handshake profile — which is why one part number covers the full range. Swapping between models in this series does not require any electrical adaptation.
- Bench tested on actual hardware: We cycled this cell through repeated charge and discharge sequences on the SGS platform. The BMS accepted the cell without error flags and the motor drive responded correctly to both open and close commands throughout testing.
- Post-install reconnect window: After fitting this battery, wait at least 60 seconds before issuing a command from the Somfy app or remote. The motor unit runs a mesh network re-join sequence after any power interruption — sending a command too early can cause the hub to log the device as unresponsive.
Why the SGS motor stops mid-travel after a battery swap
Ni-MH cells shipped in storage state typically sit at 9.0–9.2V — below the SGS motor drive's minimum operating threshold under load. When the motor starts a full blind or shutter travel cycle, current draw spikes and the weakened cell voltage sags below the BMS cutoff. The unit halts mid-travel and may appear unresponsive. Run one or two full charge cycles on the new battery before fitting it to bring the cell to rated capacity and eliminate voltage sag on motor start.
Low battery alert showing immediately after fitting a new cell
The Somfy hub reads pack voltage to determine charge state. A cell delivered in storage discharge will report a voltage that crosses the low-battery alert threshold even though the cell is new. The hub displays the warning based on that voltage reading alone — it does not distinguish between a new and a depleted pack. Charge the battery fully before installation; the alert clears once the pack reaches approximately 10.6V at rest.