Questions Regarding The Generator - SMA SUNNY ISLAND 4.4M Operating Manual

14 Troubleshooting
• The charging capacity of the battery can be influenced by the maximum AC charging current. To do this, set
Device parameters > Device > Inverter > Maximum AC-charging current to the value required.
What is the Discharge Cut-off voltage function?
• The Discharge Cut-off voltage function is relevant for voltage-controlled operation (V Loop) with a diesel
generator as external energy source within off-grid systems. In this application, the Discharge Cut-off voltage
function ensures that the battery only discharges up to a set voltage limit. The function Discharge Cut-off
voltage can be used for lead-acid and lithium-ion batteries.

14.5.3 Questions Regarding the Generator

Why is the Sunny Island not connecting to the running generator?
A high output power of the Sunny Island inverter when the battery state of charge is low may lead to the Sunny Island
not being able to raise the AC voltage in the stand-alone grid to the AC voltage of the generator. The Sunny Island
cancels the synchronization.
• To charge the battery, reduce the power of the loads.
The generator voltage might not be within the thresholds for voltage and frequency.
• Check whether the voltage and frequency of the generator are within the thresholds set (see technical information
"Parameters and Measured Values" at http://www.SMA-Solar.com).
– If the voltage and frequency of the generator are not within the thresholds set, ensure that the fuse is not
defective or that the circuit breaker is switched on.
– If the voltage and frequency of the generator are only sometimes within the thresholds set, set the thresholds
for the voltage and frequency of the generator voltage (see Sunny Island inverter installation manual).
– If the voltage and frequency of the generator are within the thresholds set, the Sunny Island is in the warm-up
period or is blocked for connection.
Why does the Sunny Island connect to the generator for only a short time?
The generator may be overloaded.
• Select Generator > Generator and set the parameter Rated generator current to 75% of the rated current of
the generator.
• If possible, reduce the power of the loads.
The maximum permissible generator voltage may be set too low.
• Select Generator > Generator and set the parameter Voltage monit. gener. upper maximum threshold to
the maximum generator voltage.
The minimum frequency for the generator voltage may be set too high.
• Select Generator > Generator and set the parameter Frequency monit. generator lower minimum
threshold to the minimum frequency of the generator voltage.
It may be that the permissible time for reverse power was exceeded (see Generator > Generator > Power
monitoring > Volt. monit. gener. max. reverse power trip. time).
• Check whether the warning Reverse power prot. (generator) has been entered in the menu Events.
• Select Generator > Generator > Operation and set the parameter Acknowledge generator errors to
Execute. This acknowledges the generator error.
170 SI44M-80H-13-BE-en-15
SMA Solar Technology AG
Operating manual