To change the minimum SOC of the battery, you must go to OS ONE. 

Once connected, you must go to the "Settings" tab in the "Battery" section. You can then access directly to the setting of the battery cut-off threshold. You have 2 SOC thresholds to set, the one with the presence of the electrical network and the one without network. By keeping a difference on these values, it allows you to benefit permanently from an energy reserve in case of network cut. Remember to confirm by pressing the "OK" button otherwise your changes will not be taken into account. 

Note: The lower your "SOC" is, the more you will increase the useful energy capacity (charged and discharged energy) but you will decrease the lifetime of your battery.