Xantrex Technology power Inverter Stacking - Manual (Page 20)

Installation
2–2 975-0059-01-01 Rev A
DC Wiring
The success of series-stacked, inverter systems is dependent on the quality and
maintenance of the DC connections. Stacked inverter sets are far less forgiving to
long, undersized, uneven, and/or poor connections than are single inverters.
Battery Requirements for Series-stacked Inverters
When inverters are “stacked” they must operate from a common battery bank. In
other words, the DC negative of one inverter must be common with the second
inverter and likewise for the DC positive.
For example:
If you have eight 6-volt batteries in a 24-volt configuration, they would be
arranged in two rows of four batteries (see Appendix C of the Sine Wave Plus
Owner’s Manual for diagrams of various arrangements). The negative ends of
the two “strings” of batteries must be jumpered together to become common
with each other. Likewise, the positive ends of the two “strings” must also be
jumpered together so that they are also common with each other.
Battery-Bank Configuration for Series-stacked Inverters
When using inverters in a stacked configuration, the same battery bank must be
used for both inverters. To ensure even charging of the batteries, each inverter
must be connected to both strings (i.e., positive cable to string two, and negative
cable to string one for inverter 1, and positive cable to string one and negative
cable to string two for inverter 2) as shown in
Figure 2-1 . In other words, a
separate positive (+) and negative (–) cable pair is required for each inverter in the
series-stacked configuration. This means there will be four battery cables from the
stacked inverters to the battery bank.
Refer to the Owner’s Manual for the Sine Wave Plus to determine the correct size
and length of cable required.
Figure 2-1 Example of Battery Connections for Series-stacked Inverters
(24 Vdc shown)
DC conduit for
L2 Inverter
– +
12 Volt
Battery
200 Ah
– +
12 Volt
Battery
200 Ah
+ –
12 Volt
Battery
200 Ah
Series String 1
Series String 2
DC conduit for
L1 Inverter
24 Vdc/200 Ah
24 Vdc/200 Ah
– +
12 Volt
Battery
200 Ah
Series-strings
wired in Parallel
24 Vdc/400 Ah