M-4 Plugs, or Chop'm Off

2oldman wrote:

BFL13 wrote:

2oldman wrote:
For the winter months I'm usually sitting at about 60° tilt.

What Lat are you at in the winter months though?

Palm Springs latitude.

So using Lat 34N to make it simple, then on 21 Dec with Dec about 23.5S, tilt at noon would be 57.5 degrees ( your 60 degrees.) Then tilt reduces by 8 degrees a month till on 21 March it is 34 degrees.

21 Jan would be about 50 degrees. I see macslab says in winter optimum tilt is Lat x 0.89 plus 24 degrees. So 34 x.089 = 30.26 plus 24 = 54.26.

So he is taking declination for the winter three months to be 54.26 - 34 = 20.26S which is only 3 degrees (one and a half weeks) after 21 Dec. IMO that would make the tilt a little high for most of the winter, especially in March, when daylight is longer and you do get some shoulder hours light that needs the panel lower to see it.

So all in all you have a range of tilt for Palm Springs from 57.5 at Xmas to 34 if you stay till 21 March. Pick a tilt somewhere in the middle of that for most AH or figure it out for your actual dates there.