what kind of wire to extend from Solar Panel to Controller?

I have 6 of 260W 24V Solar Panels.
They are Parallel because I am using a 24V System.
Each module put out 8.37AMP
I have a total of 50.22 AMPS
As my previous question, I now have a Combine Box with appropriate Breakers.
So next question is, what kind of PV wire to use from the Combine box to the Charge Controller?
My extension is 90FT at least.
I was thinking to go with 8 AWG PV wires. Will this do?
They are Parallel because I am using a 24V System.
Each module put out 8.37AMP
I have a total of 50.22 AMPS
As my previous question, I now have a Combine Box with appropriate Breakers.
So next question is, what kind of PV wire to use from the Combine box to the Charge Controller?
My extension is 90FT at least.
I was thinking to go with 8 AWG PV wires. Will this do?
Comments
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
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Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
Some of the higher powered (300+ watts) 60 cell panels have higher voltage than older, lower watt panels. So it seems the lines have blurred as to whether a 60 cell panel is appropriate for 24 volt charging. The 260 watt panels in question are, well, questionable.
2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.
Getting back to the original question, here is a link to a ampacity table.
https://xtronics.com/wiki/Wire-Gauge_Ampacity.html
If the wire is enclosed, 8 gauge only has a max capacity of 46amps, so no, it isn't adequate. Getting back to running your panels in series, if using a 3S2P configuration, you'd be producing <17amps at 93V, so 8 gauge would be more than adequate. In the real world, you might never actually see full amperage, but you are working around the ragged upper edge, which is never advised.
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
Using this voltage drop calculator on the distance mentioned
http://www.calculator.net/voltage-drop-calculator.htm
you loose 5.65 volts. That drops the end voltage down to 25.35, which will NOT adequately charge your 24 volt bank.
Using the same calculator, it shows you don't get above 29.5V till you use 2 gauge wire
Like everyone is saying, you need to go serial and MPPT.
You really need an STC rated Vmp-array~17.5-20 volts (12 volt battery bank) or ~35-40 volts (24 volt battery bank) for a PWM charge controller.
When you add long wire runs and/or an MPPT charge controller, then you are looking at 45-50+ volts Vmp-array-stc (standard test conditions) minimum.. It is pretty common practice to run a MPPT controller Vmp-array input at ~2x nominal battery operating voltage (i.e. 24-30 volts (nominal-charging) volt battery bank ~48 to 60 volts).
-Bill