Outback Power Systems 80 user manual Determining Wire Sizes, Wire and Disconnect Sizing

2. Determining Wire Sizes

Open Circuit Voltage/Wire and Disconnect Size

Maximum Open Circuit Voltage (VOC)

•VOC is the unloaded voltage generated by the solar array.

•Greater than 145VDC G FLEXmax 80 suspends operation to protect components

•150DC G max open circuit voltage with the coldest environment

NOTE: Although the FLEXmax 80 shuts down at a voltage greater than 145VDC, it can withstand up to 150VDC from the array; anything higher than 150VDC will damage the FLEXmax 80).

•As every brand of panel is different, be sure to know the manufacturer’s specifications.

•Weather conditions vary and will affect panel voltage.

•Hot weather: lower open circuit voltage/lower maximum power point voltage

•Cold weather: higher open circuit voltage/higher maximum power point voltage

•Allow for ambient temperature correction using the following table:

25° to 10° C (77° to 50° F)	multiply VOC by 1.06
9° to 0° C (49° to 32° F)	multiply VOC by 1.10
-1° to -10° C (31° to 14° F)	multiply VOC by 1.13
-11° to -20° C (13° to -4° F)	multiply VOC by 1.17
-21° to -40° C (-5° to -40° F)	multiply VOC by 1.25

• Check the PV array voltage before connecting it to the FLEXmax 80 (see page 76)

Wire and Disconnect Sizing

•The output current limit of the FLEXmax 80 is 80 amps.

•Use a minimum of 4 AWG (21.15 mm2) wire for the output between the FLEXmax 80 and the battery bus bar conductors.

•Install OutBack OBB-80-150VDC-PNL breakers for disconnect and overcurrent protection.

•The largest PV array that can connect to an FLEXmax 80 must have a rated short-circuit current of 64 amps or less under STC (Standard Test Conditions).

•Input conductors and circuit breakers must be rated at 1.56 times the short-circuit current of the PV array. OutBack 100% duty continuous breakers only need to be rated at 1.25 times the short-circuit current.

•Please see the wire Distance Chart and complete Wire and Disconnect Sizing on pages 77-79 for other suitable conductor/wire sizing.

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