Design Sanity Check Please

[Rafagus]

My goal is to run my 4 240v Mini Splits from solar when it's available. My panels will be atop an out building 150' from my house. My "solar room" will be in the shop.
I think I should:

• Run 2 sets of 8 AWG copper. 1 set bringing grid power to my all in one inverter and another set carrying the load back to the mini splits.
• I used this calculator to come up with the wire size. I spec'd 40 Amps as the "current at end of cable run".
• I've never seen my Mini Splits draw over 4 Amps each, so 16 amps total.

I'm about to dig the ditch for wire between my shop and house. At this point I just want to make sure I put enough wiring in the ground.

Your advice please!

 

[timselectric]

#8 will carry the 40a over 150' , with no problem.