Installation Manual

Planning
12 900-0197-01-00 Rev A
EXAMPLE #2
A. Loads: 1 kW (1000 W)
B. Hours of use: 3
C. Days of autonomy: 1
D. Off-grid system (FX3048MT inverter)
E. Conductor efficiency: 97% (0.97)
F. Inverter efficiency: 93% (0.93)
G. System voltage: 48 Vdc
H. Batteries: OutBack EnergyCell 200RE (12 Vdc)
I. Capacity at 8-hour rate: 148.8 Ahr
J. Maximum DoD: 50% (0.5)
Generator

The FX inverter can accept single-phase input from a generator that delivers clean AC power in the range of
voltage and frequency specified for that model.
~ Inverters stacked for split-phase output (120/240 Vac) can work with both output lines of a split-phase generator.
See pages 30, 32, and 36.
~ Inverters stacked for three-phase output can work with three-phase generators. See page 38.

The inverter/charger can provide a start signal to control an automatic start generator. If automatic generator
starting is required, the generator must be an electric-start model with automatic choke. It should have two-wire
start capability. For other configurations, additional equipment may be required.

In any configuration, the inverter may need to be specifically programmed using the system display.
Perform all programming according to the specifications of the generator and the required operation of the
inverter. Parameters to be programmed may include generator size, automatic starting requirements, and
potential fluctuations in generator AC voltage.
Mobile generators are usually equipped with a bond between the neutral and ground connections. Mobile FX
inverter models have neutral-ground switching. This function establishes a bond on the inverter when no
generator is present, but removes it when the generator is running. See page 15 for more information on
neutral-ground bonding.
Generator Sizing
A generator should be sized to provide enough power for all the loads and the battery charger.
The generator size should assume maximum loads and maximum charging at the same time.

Available generator power may be limited by ratings for circuit breakers and/or generator connectors.

The generator must be able to provide current to all inverters on a given phase or output. Minimum generator
size
3
is usually recommended to be twice the power of the inverter system. For example, a 2 kVA inverter should
have a 4 kVA (or larger) generator. Many generators may not be able to maintain AC voltage or frequency for
long periods of time if they are loaded more than 80% of rated capacity.

In addition, if a split-phase 120/240 Vac generator is powering a single-phase 120 Vac inverter system with no
other compensation, it is
required
to be at least twice the power of the inverters. A split-phase generator that is
heavily loaded on one output line may suffer severely from balancing issues. The OutBack FW-X240 or PSX-240
balancing transformers may compensate for this condition.
IMPORTANT:
In general, the generator output should match the stacking and output of the inverters.
A three-phase generator should not be used with a 120/240 Vac inverter system.
A purely 240 Vac generator will cause damage if used with a 120 Vac inverter system.
3
This is the generator size after derating for environment, use, and other factors.
1) A ÷ [E x F] 1000 ÷ (0.97 x 0.93) = 1108.5 W
2) 1 ÷ G 1108.5 ÷ 48 = 23.1 Adc
3) 2 x B 23.1 x 3 = 69.3 Ahr
4) [3 x C] ÷ J [69.3 x 1] ÷ 0.5 = 138.6 Ahr
5) 4 ÷ I 138.6 ÷ 148.8 = 0.93 (rounded to 1)
6) [G ÷ H] x 5 [48 ÷ 12] x 1 strings = 4 batteries