Introduction
Relay control based on the total battery state of charge
This special local control mode switches one or more relays on when the total state of charge of all the batteries on the site drops below a configurable value, and off again when it rises above another value. It is the general-purpose version of Switching on a generator at low battery state of charge: use it for any load or signal that must follow the state of charge of the batteries, for example a warning lamp, a load that may only run while there is enough energy in the batteries, or a contact towards a building management system.
- Below the lower threshold, the selected relays are switched on.
- Above the upper threshold, the selected relays are switched off.
- Between the two thresholds, the relays keep their position (hysteresis), and a relay stays at least the configured minimum time in the same position.
Note
The total state of charge is the capacity-weighted average of the state of charge of all the batteries of the site.
Note
The timing settings of the relays (minimum and maximum switch on and off times) are ignored in this mode. Only the minimum hold time configured in the mode itself applies.
Warning
If the total battery capacity is zero (no batteries, or batteries without a configured capacity), the mode cannot decide and puts the relays in their default device state. The mode reports this as an error on the external signals page.
Configuring the special control mode
Batteries
Make sure that your batteries are added to the SmartgridOne Controller.
Relay device settings
- Add the relay through the device wizard, see Adding a device: choose 'On/off load', 'Generic', and then 'Relay' or 'Ethernet to relay converter', as suited to how the relay is connected.
- In the device settings of the relay, set the 'Default device state' to the position the relay must take when the mode cannot decide. The mode itself puts the 'Use case' of the relay to 'Direct passthrough of an external control signal' as soon as it is active.
Enabling the special control mode
- Go to the 'Settings' tab of the SmartgridOne Controller's interface and click "Manage special local control modes".
- Click "Start wizard" under "Enable a new special local control mode".
- Choose "Relay control based on the total battery state of charge" and click "Next".
- Configure the mode:
- The total battery state of charge (as a percentage) below which the relays should be switched on.
- The total battery state of charge (as a percentage) above which the relays should be switched off.
- The minimum time (in seconds) the relays should remain in the same position.
- Select the relay(s) and click "Apply mode to selected devices".
See Special local control modes for the priority towards other signals, and for pausing or removing the mode.