Product Manual

Operation
36 900-0145-01-01 Rev B
Multiple-Inverter Installations (Stacking)
Multiple inverters in a single system can support larger loads than a single inverter can handle.
Installing inverters in this configuration is called “stacking”. Stacking inverters does not refer to
physically placing one on top of another. It refers to how they are wired within the system and
then programmed to coordinate activity. Stacking allows all units to work together as one system.
The GS7048E and GS3548E models can stack up to ten units in parallel for increased capacity. For
three-phase output, up to nine models can be stacked, three per phase.
Stacking requires an OutBack HUB Communications Manager, as well as a MATE3 system display.
There are usually other specialized stacking instructions during installation.

A system of four or fewer units may use the HUB4.

Systems of up to ten units require the HUB10 or HUB10.3.

All interconnections between the products are made using CAT5 non-crossover cable. (See the Radian
Series Inverter/Charger Installation Manual for more stacking instructions.)
Each inverter needs to be assigned a status — “master” or “slave”. The master is the primary and most
heavily used unit. Slave inverters provide assistance when the loads are more than the master can
handle alone. In addition, in a three-phase system, “subphase masters” allow control of outputs that
the master inverter cannot monitor.
Programming involves using the MATE3 to assign a status and stacking value to the inverter on each
port. See the MATE3 and HUB manuals for programming instructions.
Figure 7 OutBack HUB4 and MATE3
IMPORTANT:

The Radian GS7048E can be stacked with the Radian GS3548E in either a
parallel or a three-phase configuration.

The master inverter must always be connected to port 1 on the HUB.
Connecting it elsewhere, or connecting a slave to port 1, will result in
backfeed or output voltage errors which will shut the system down
immediately.

All stacked Radian inverters must have the same firmware revision. If
inverters are stacked with different firmware revisions, any unit with a
revision different from the master will not function. The MATE3 will display
Additional Ports
Port 1
MATE Port
HUB4
MATE3