Lithium-ion batteries only: Setting equalization charge of the batteries
Equalization charge of batteries is applicable in systems in stand-alone and parallel grid-operation mode. A regular equalization charge is always useful if a full charge of the battery up to a SOC of 100% is never or only rarely achieved during normal operation. This applies to the following battery-storage systems:
Systems for increasing self-consumption that are not intended to feed in any excess PV energy (zero feed-in systems) and therefore switch off the PV system by means of a contactor before the battery state of charge reaches 100% SOC (see planning guidelines "PV systems with zero export"). Here, the source of equalization charge is the utility grid.
Off-grid systems powered by a PV inverter and a generator as an external energy source. Due to seasonal fluctuations, a battery state of charge of >95% may not always be achieved. Here the source of equalization charge is the external energy source (e.g. diesel generator).
To activate the equalization charge for lithium batteries, there are the following possibilities:
Set manual equalization charge.
Set automatic equalization charge.
Set manual equalization charge
The manual equalization charge performs the procedure only once. A started equalization charge can be terminated via Stop.
Procedure:
- Select Battery > Battery > Operation.
- Click the On button to activate Manual equalization charge.
- Click the Off button to deactivate Manual equalization charge.
Set automatic equalization charge
Display of irrelevant parameters
When connecting lithium-ion, some parameters are displayed in the Battery > Charge menu that are not relevant for automatic equalization charge and cannot be set:
- Time for fast charging / Time for equalization charge / Time for full charge / Final discharge voltage
- Cell charge nominal voltage for boost charge / Cell charge nominal voltage for full charge / Cell charge nominal voltage for equalization charge / Cell charge nominal voltage for trickle charge
- Full charge cycle time Temperature compensation
- Setpoint of the battery charging voltage with disabled battery management system
Parameter | Explanation |
|---|---|
Automatic equalization charge | If automatic equalization charge mode is set to On, the Sunny Island automatically starts and stops equalization charge within the limits of the set values. The value Off stops the automatic equalization charge mode. These selections apply to both lead-acid and lithium-ion batteries. |
Time until equalization charge has been completed in SOC range 1 | Fixed SOC ranges are assigned to these 2 parameters:
When the respective SOC range is reached, monitoring of the respective set time period begins. After the respective time set for 1 of the 2 SOC ranges has elapsed, the equalization charge is considered to be completed and the battery discharge is released again. |
Time until equalization charge has been completed in SOC range 2 | |
Time until interrupting the equalization charge for lithium-ion batteries | If neither SOC range 1 nor SOC range 2 could be completed within the time specified by this parameter, the equalization charge is interrupted. In this case, the event message Equalization charge interrupted appears. |
Equalization charge cycle time | When the time specified by this parameter has elapsed, the Sunny Island will again attempt to perform an equalization charge. |
Procedure:
- Select Battery > Charge.
- Click the On button to activate Automatic equalization charge.
- Click the Off button to deactivate Automatic equalization charge.
- If automatic equalization charge is activated, set the following parameters: Time to complete equalization charge in SOC range 1, Time to complete equalization charge in SOC range 2, Time to abort equalization charge for lithium-ion batteries and Cycle time for equalization charge.