Solar panel wire question
So have a ground mount system that is going to be axitec 270w panels 46 of them equal to 12420 watts but will be upgrading to 16kw in later future so I need to size the wire larger. I am not sure if i will go with aps320 invertors or 2 solar edge 6000. The distance from the panels to the house panel is 150 ft. i would really like to put the solar edge in the basement because of its 50 degrees all time and that's what I want. but if I go with solar aps micro invertor i would be running a ac wire to the panel where as the solar edge in the house would be a dc wire . What wire size would i have to run if i had a solar ege in house for the two solar edges and how many wires ? What wire size would it be if i ran a ac wire to house ? tks in advance
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|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
Regarding aluminum--The problem with aluminum is not the absolute maximum operating temperature for aluminum but the mechanical properties of the metal.
When compressed (installed binding screw), the aluminum can get hot and "extrude" from under the (improperly designed) binding screw/system. Then when the joint cools (at night for example), the aluminum contracts and leave a little air gap between the binding surface and the aluminum. The exposed "raw aluminum" (in minutes" developed a insulating oxide which reduces contact area and eventually cycling will increase the joint resistance causing it to overheat and possibly catch fire.
In theory, the newer CU/AL rated connections are not supposed to do this... Or you run your main run with (~3 AWG heavier) AL main cable and use approved compression fittings at each end to convert from AL to Copper pigtails. Aluminum and rated compression fittings (crimped with the correct tools) are very secure and reliable (hermetically sealed) and used on pole to house drops "everywhere" in the US (at least in my region).
If you want to run copper--That is fine (and would be my personal preference). But many have used Aluminum too.
Sending the power longer distances (in terms of residential scale systems)--Does not matter if AC or DC. Running Vmp-array at ~300-400 volts is a lower current than ~240 VAC nominal--So you can use smaller diameter cable and/or send farther distances.
Also--It does depend on what and where you need your power... if you need no AC power near your solar array (no out buildings, no water pumping, etc.), then sending 300-400 volts Vmp-array power is (in theory) the least costly solution. Also, voltage drop and variations do not matter to the GT Inverter--It takes whatever Vmp-array*Imp-array and converts that to your local ~240 VAC (if single phase) power.
If, however, you need 120/240 VAC at the array (out building, etc.), you can run the GT Inverter (or micro inverters) at the array and run a 240 VAC branch circuit from the "house to the out building" so you have your one long run servicing both the GT Array and your local power needs. Note that running long cables of 240 VAC at high current levels (shop tools, GT Solar pushing current back to the home) can end up with voltage drop and voltage "rise" (i.e., the "backwards current flow" from GT solar)... (I.e., if your high line is ~255 VAC and you have a 3% rise or +7.65 volt rise--You are really close to where the GT inverter is supposed to shut down for safety (typcially around 260-264 VAC is shutdown). For folks at the end of the rural power lines, sometimes there is a wide range of AC mains voltage (summer/winter/local processing plants/etc.).
Running DC voltage to the GT inverter at the home removes Voltage "rise" as an issue for the long branch circuit.
I hope this helps--A lot of typing and hand-waving here.
-Bill
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
https://www.solaredge.com/us/products/installer-tools
At this point I guess you understand that you would be running higher voltage with a common inverter, than with micro inverters, though DC current.
- Assorted other systems, pieces and to many panels in the closet to not do more projects.
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
I don't deal much with grid tied systems. I think current requirements are to have a disconnect that is accessible on the outside of the building, and I think it's integrated into the inverter. Do your research.
- Assorted other systems, pieces and to many panels in the closet to not do more projects.