SMA Sunny Island 4248U, Installation & Operating Instructions Manual

Page: 44 / 100

Split-Phase SI4248U Manual
36
Split-Phase
Split-phase Systems
The Sunny Island 4248U has the ability to work together in split-phase mode with another
Sunny Island 4248U to provide 240 V AC capabilities.
When used in split-phase mode, one inverter is set up to be the “Master” unit, and the other
the “Slave” unit. Basically, the master unit controls all functions of the inverters as a whole, and
the slave unit merely provides the other 120 V AC leg. For example, all the battery charging
functions are controlled only by the master unit.
To set the inverters up for split-phase mode, they must first be completely wired and ready to
operate. Both inverters need to have a battery temperature sensor connected to them (the slave
unit’s battery temperature sensor is only required for set-up and then it can be removed. There
is no need to place the slave unit’s battery temperature sensor in conduit, it is temporary). Use
the following wiring diagrams for guides when wiring the inverters for split-phase.
Figure 1-19 AC and DC Wiring for Split-Phase
Only 240 V generators with center tap (or 120 V with autoformer) may be used and connected
to the system as shown in figure above.
.
0
.
.
0
.
/CUVGT 5NCXG
5JKGNF %
#
0A.
%A)0& %#
0
A
*
5JKGNF %
#0A.
%A)0& %
#0A*