Outback Power Integration Guide

REV042920
SimpliPhi Power, Inc. | 3100 Camino Del Sol | Oxnard, CA 93030, USA | [phone] | [e-mail]| SimpliPhiPower.com
| 9 |
12V Inverter Model
Inverter
Power Rating
(kW AC)
Inverter
Efficiency
Load
Rate (kW
DC)
PHI 1.4 - 12.8V
nom
MIN Battery Quantity
PHI 730 -12.8V
nom
MIN Battery Quantity
OutBack VFXR 2812A
2.8
90%
3.1
7
9
OutBack FXR 2012A
2
90%
2.2
5
7
3.2 – Sizing for Maximum Instantaneous Charge Rate (DC Coupled)
In a DC Coupled system, the solar PV array output can be curtailed using charge controllers. However, reducing
the solar array’s power output using charge controller programming implies that the PV array’s output is also
reduced for the entire remainder of the system, including the solar power available for powering loads and for
exporting to the grid. Furthermore, greatly reducing the PV array’s output via the charge controllers effectively
wastes the solar PV array’s power and puts strain on the charge controllers.
Calculate the minimum quantity of PHI Batteries needed to prevent over-charge from the solar PV array by
considering both the solar array size and the charge controller’s potential output. Whichever value is
less should
be used to size the PHI Battery Bank. If the solar array’s maximum potential current output is less than the paired
charge controller’s Output Amps rating, then the solar array’s maximum potential current output can be used to
size the PHI Battery bank. If the charge controller’s Amp rating is less than the solar array’s maximum potential
current output, then the charge controller’s rating is used to size the PHI Battery bank.
Divide the system’s potential charging current by the MAX Continuous Charge Rate per PHI Battery (found in
Table 1.0 or on the relevant battery’s specification sheet) to calculate the minimum quantity of PHI Batteries
needed to ensure that the solar PV array does not over-charge the battery bank.
Example A: Three PHI 3.8 kWh-51.2V
nominal
batteries (used in a 48-Volt system) must be paired with a 4,500-
Watt solar PV array wired to an 80 Amp-rated charge controller. In this case, the 80-Amp charge controller is
used to determine the minimum PHI Battery quantity needed to prevent over-charging from the solar PV.
 =  × 
4,500     =  × 48 
4,500 
48 
= .   =      
80  < 93.75  →   =       ℎℎ ℎ ℎ 
(
  ℎ 
)
÷
(
 ℎ   
)
=      ℎ
(
80
)
÷
(
37.5
)
= 2.13 →   