Both interesting points. My assumption in regards to snow was similar to your statements. There’s a few comments in here that have me second guessing that.
But then one must also consider that
@Zwy says he’s got consistent temps of -20F and I simply can’t relate to that. Maybe that’s why it lacks opportunity to melt as that’s simply brutally cold.
I hope I fare better with longest cold stretches being a week of lows around 0 to 5F, otherwise your squeegee idea may come into play.
Your second piece about sunset and only gaining 30min to an hour is a bit surprising to me. I’ve been trying to understand the data of E/W arrays to extend production hours thus reducing battery demand but an hour or less is much different than 2-3. Hmm.
I can only go by observed. As far as summer vs winter, the sun simply does not shine as much in the winter, so there is a loss there, however I look at my curves and it just doesn't jibe with "what it is supposed to be". I have 32 panels flat on a 2/12 roof. That is WAY under optimal, like < 20 degrees of pitch and yet even now my peak output can hit close to10KW on the 14.5K of roof panels.
Nice thing about Phoenix is the sun is pretty consistent, to the point of monotony. My Solar production curves are generally as smooth as glass.
Had to go back a few days when I charged my car, and took a full days solar production. The dark blue humps at 9:15 and 11 were from me moving the car that was blocking the sun from B-PV3 (a yard ornament, that I actually sold today) and then re-stacking some panels that had fallen off the blocks. The curve is now smooth subsequent days.
'A-PV3' is 7x250 is currently facing due west, maybe slightly south (260/265ish) at about 35-40 degrees. B-PV3 is 8x250 laying flat on cinder block. As in just laying on the ground, with a 6x8x8 cinder block at each corner, as in my back yard slopes slightly to the north. I'm going to re-arrange a little, this weekend, but we actually have some clouds coming in starting tomorrow and that wet crap might fall from the sky on thursday and friday, so I won't have anything to graph until the sun comes back out. Dec 21/22 is just around the corner so the world is going to wobble around kinda funky for the next few months until we get closer to the equinox this spring. You can see the difference though the slightly smaller by 15% A-PV3 string actually matches output with the decidedly sub-optimal B string around 1530. By 1630 they are both pretty much done. the flat laying panels dying out about 15-20 minutes ahead of the west facing ones. There is a block wall to the west and the A string is actually elevated about 2 feet vs 8 inches on the flat panel, so I'm not sure it would even be that drastic if they were both up about 3 feet or so.
I've shuffled these panels around 7 ways from sunday, but you can see the due west panels don't catch anything until after 9. Frankly I think the best bet now that I have more battery is likely mostly south with a slight westerly azmuth for the late summer sun, just grab the maximum light and store what I can. Optimal angle for year round is supposedly just your lattitude, so like 33ish here, I think the range is 18 to 45 or something here in Phoenix, and I would guess Texas and most of the places along this lat, probably just don't suffer that much from angle issues, because I think you just don't take that much loss up to about 30% off TDC.
For me, power consumption is generally drastically lower here in the winter, so daily power requirements have dropped to 30-40%. At the moment I'm producing 60KWH and using 35-45/day depending on car charging depletion. Peak production this summer was around 105KWH, generally closer to 95, and I was using as much as 115, generally around 100.. So I'm getting around 60-65% of my summer output, the bulk of the loss because the day is way shorter.
All that being spewed, a panel covered with snow produces pretty much 0KWH, so if that is a consideration, and adding 30 or 40 degrees of pitch generally keeps the snow off in the winter, that would seem to be a "no-brainer", You get a winter power bonus, and you don't have to manually remove extra white stuff. OTOH, I don't believe a tracking system is ever going to pay you back, and somehow I think putting a bunch of hinges and gears that move thru the day is not going to improve reliability. I think Tim's 'Winter Panel placement' idea is the ticket, just the opposite of me seasonally. You just point and pitch everything for the worst production/use ratio days so you can grab and store every scrap because you need it. Then in the summer when it's plentiful you don't really care if it's optimal because you toss way more than you can use anyway.
