Glenn Herbert wrote:I notice that, aside from the unavoidable waste from panel geometry, the panels could all be made a couple inches bigger from the 4x8 sheets, making the whole structure maybe 6" bigger in diameter.
I do think that in terms of usable space beyond raw floor square footage, you could get pretty close to the same with ten sheets of plywood making an 8' x 8' cubish structure with a gable roof and 6' eaves and 8' ridge. The parts would be much easier to make and quicker to assemble, and very easy to waterproof. With 12 sheets, you could make an 8' x 10'-8" structure with 6' minimum walls.
Michael Qulek wrote:
R Scott wrote:There is higher efficiency when the inverter can convert directly from solar instead of charging the batteries and then pulling the power out for the inverter. Choose the string that gets direct light when you use the most power
I don't think this statement is correct. As far as my understanding goes, ALL solar power passes through the controller into the batteries, and then All power comes out of the batteries to fuel the inverter.
What you might be thinking about is system potential, instead of battery voltage? When sitting idle at night time, with no power coming in, the system potential is the voltage of the battery. In daylight however, the system potential is the battery voltage, plus the charging voltage. So, for example, a fully charged 24V battery bank at 8pm might be 25.4V, but the system potential would be ~28-29V towards the end of the absorption phase during the day.
The system potential becomes very important when you're trying to run a very big load, such as a 240V well-pump. A BIG load like the well-pump could cause so much voltage drop that the inverter shuts off from a low-voltage warning. While charging, the higher system potential prevents inverter shutdown because the battery has to first drop from a higher potential, and because power is coming into the batteries, the voltage sag will not be as great.