I'm in the middle of installing a solar system, and have a couple of questions:Heavy Duty Tinned Copper Lugs crimped onto Copper stranded wire -- Use any anti-corrosive or conductive grease type material in the joint before crimping it? Or better to use nothing? FYI, I do use a high quality adhesive-based clear shrink wrap on crimped joints.I am putting five 100 watt panels on the roof, non-tilting mounts. My question is, what is the recommended slight angle to mount solar panels for the purpose of rain run-off?Thanks in advance for any recommendations!

I have seen something somewhere recently not to use any goop in there like that, but can't pin it down at the moment. Was in one of the owner's manuals for something, not to use any of that red spray stuff you use on battery posts. Might not be the same as what you are asking about.5 degrees to get run off, but the roof may already be at that with camber.

BFL13 wrote:I have seen something somewhere recently not to use any goop in there like that, but can't pin it down at the moment. Was in one of the owner's manuals for something, not to use any of that red spray stuff you use on battery posts. Might not be the same as what you are asking about.5 degrees to get run off, but the roof may already be at that with camber.Thanks. Yeah, I think I read something recently somewhere also recommending to put nothing. I used to put Ox-Gard on such connections, but now I am questioning the wisdom of that.My roof is very close to flat, though must be rounded ever so slightly to each side. I was thinking for the two panels nearest the front of the TT, to tilt them down slightly toward the front due to forward motion when traveling, but I suppose any such angle like 5 degrees or so is so slight that it probably doesn't matter which direction they are tilted in.

Does the solar panel manufacturer suggest any tilt for rain?

solar panel MFG don't need a rain run off recommendationsolar panel MFG always recommend 90 degrees to the azimuth of the sun ( rain run off recommendation Not needed )that is way more than the 5 degrees recommended here

Crimp clean and dry. You can do an empirical test to see what angle sheds enough water.

Solar: Add Anything to Copper Crimps & Tilt Angle for Panels

crcr
Explorer
Dec 16, 2019
BFL13 wrote:
The installation instructions for my Sharp panels I had a few years ago said minimum 5 degrees for rain drain. Warned about puddles on the panel making for "hot spots" (ISTR that was the term) and damage to cells.

EDIT Read up some on that. Hot spots caused by shading with uneven heating. "Self-cleaning" by rainfall to clear off dust--most say at least 10 degrees. Panels have drain holes that should be kept clear.

My Canadian Solar brand panel installation guide does not mention tilting for rain like my old Sharp one did.

I have nearly flat panels on the Class C roof, and have seen how rain puddles make for dirty areas after they dry if the panels are dusty before it rains. That might lead to shading related hot spots if not washed. I clean my panels fairly often anyway.

Thanks, BFL, 10 degrees or more makes sense, in order to get good rain run-off and dust wash-off, and eliminate any puddling of water after a rain.

I'm installing five 100 watt panels, so I'm thinking of not angling them all the same direction. Even though installed at say a 10 degree angle, yes, at some times of day, the panels angled the slightly opposite way to the sun will provide a little less production. But at the same time, when the sun is in the opposite side of the sky, the panels angled the opposite way may provide a bit more production, so seems like it would balance out.
BFL13
Explorer II
Dec 16, 2019
There was something about PID too and they were saying that with a panel tilted a bit, you can get a puddle at the low end dammed by the frame being a tad higher than the cells, which then sort of leaks into the works. Not too clear on that risk.

IMO go flat and just keep them clean.

Direct sun normal to panel gives the most amps and amps go down more the angle is off direct. Additional 10 degrees not linear so makes it more in the shoulder hours, when the flat panel is already at a disadvantage for angle.

full_mosey posted about this if I can find it.

https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/25542183/gotomsg/25562549.cfm#25562549

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