Boost Charge; Full Charge - SMA SUNNY ISLAND 4548-US Operating Manual

SMA Solar Technology America LLC

13.5.1 Boost Charge

The boost charge is the most common charging process of the Sunny Island. The boost charge ensures
a high generator workload through a high charging voltage over a short period of time. With liquid
FLA lead-acid batteries, this charge process should be used for gassing and thus compensating the
electrolytes. The boost charge process can charge the battery up to approx. 85% to 90%.

13.5.2 Full Charge

Every 14 days or after eight nominal charge throughputs, the Sunny Island automatically initiates a
full charge (parameter "222.05 CycTmFul").
Nominal charge throughput
A nominal charge throughput is reached when the sum of the discharge currents corresponds
to the nominal capacity of the battery.
Example: The battery has a nominal capacity of 100 Ah. A nominal charge throughput is
reached when the battery has been discharged ten times for one hour by 10 A.
The objective is to recharge the battery to a state of charge of at least 95% and rectify possible effects
caused by an insufficient charge. Regular full charging approximately every two to four weeks can
double the battery life.
Change to full charge
If the Sunny Island changes to full charge after a specific time of boost charge has elapsed, the
entire time of boost charge elapsed is considered for full charge.
More than 1% of the nominal battery capacity is discharged
If more than 1% of the nominal battery capacity is discharged during a full charge, 50% of the
time elapsed is considered for the next constant voltage phase.
External charging device
If an external charging device or charge controller is connected to the battery and the criteria
for a full charge are fulfilled due to external charging, the Sunny Island treats this as if it had
performed the full charge itself.
Parallel procedures for full charge
Any parallel procedures causing the generator to stop during full charge are not taken into
account until the charging process is completed.
Operating Manual
13 Battery Management
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