Alpha Group OutBack Power FLEXmax Extreme Series, Owner'S Manual

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900-0150-01-00 Rev A
69
Applications
Array Design
Sizing Guidelines
Below is a list of maximum array wattages for the FLEXmax Extreme for various nominal voltage batteries. This
should be used for sizing an array. Note that every PV module is different. The specifications for every model
should be consulted before designing or assembling a PV array.
Table 11 Maximum Input Wattage Per Charge Controller
Nominal Battery
Voltage
Maximum Array Size
(in watts, Standard Test Conditions)
12 V 1000 W
24 V 2000 W
36 V 3000 W
48 V 4000 W
60 V 5000 W
Maximum-Power Voltage (V
mp
)
Maximum-power voltage (V
mp
) is the operating voltage for the PV array at which the array generates the most
wattage. When designing the PV array, it is recommended for the V
mp
to be approximately 12 to 24 volts higher
than the nominal battery voltage for optimum performance. This will ensure that the V
mp
is always above the
battery voltage, which is required for charging. Higher voltages are not recommended, as they may reduce the
FLEXmax Extreme conversion efficiency.
IMPORTANT:
Check the PV array voltage before connecting it to the FLEXmax Extreme.
Open Circuit Voltage (V
oc
)
Open-circuit voltage (V
oc
) is the unloaded voltage generated by the PV array. The FLEXmax Extreme controller
can withstand V
oc
of up to 150 Vdc. However, if the V
oc
exceeds 145 Vdc, the controller will suspend operation to
protect the system components.
CAUTION: Equipment Damage
Although the FLEXmax Extreme shuts down when voltage is greater than 145 Vdc, this
will not prevent the array from generating voltage. Anything higher than 150 Vdc will
damage the controller, whether it has shut down or not. The array should be designed
so that voltage never exceeds 145 Vdc in order to prevent equipment damage.