Mitigating high pv string voltage with resistance of home run wires?

[underdog5004]

I'm planning to set up a pv array, with an outback fm80 charge controller. My panels open circuit around 70v. I'm thinking about doing 2s3p config. That puts string voltage up around 140voc, at 25° C. I think I'd exceed 150voc when temps get down to around -4° C. It's not unlikely for this to happen, during nights and probably early morning, during winter.

However, I'll be losing around 6% volts due to the long (300ft) home run between array and charge controller.

Is it a bad idea to depend on this voltage drop to give the charge controller more breathing room? I'd use 300vdc breakers at the combiner box and 150vdc breakers in the power shed where the CC would be.

 

[AntronX]

No because wire voltage drop is dependent on current. At no current (when controller in float mode) there will be no voltage drop and your controller will receive Voc in full.

 

[underdog5004]

No because wire voltage drop is dependent on current. At no current (when controller in float mode) there will be no voltage drop and your controller will receive Voc in full.

I thought that might be the case, thanks for confirmation!