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paulz
Member
# Posted: 2 Mar 2021 16:32
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I've concluded my big panel washing test, at least for now. Yesterday I just sprayed them off with the garden sprayer, which is about as strong as peeing on them. But it did up the amps from 2.3-2.4 to 2.5-2.6. This morning I could see not much dirt had been removed, so I got out the soap and sponge. That really helped, sitting at 3.6 now. Hard to gauge because of altering shade, time of day but it does jibe with what I noticed last time it rained. A marked improvement, I'm happy.

gcrank1
Member
# Posted: 2 Mar 2021 17:06 - Edited by: gcrank1
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Well, If you are at all like me (old guy) you couldnt pee that high or long enough.......I prefer the garden sprayer for that kind of stuff
Some of the vanny's even use em for shower units by replacing the wand with a kitchen sink hose/spray head.
Works pretty good for spraying off muddy boots too.

paulz
Member
# Posted: 4 Mar 2021 09:23
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Went up on my shop roof to steal a few panels for my cabin yesterday, those panels were really dirty, no surprise considering the tree canopy above. Now I'm thinking about some kind of slippery coating, like Rainx or that new ceramic wax I put on my truck. That stuff is so slippery I can hardly set anything on the hood without it sliding off. Rain too slides off.

Don't want to upset the performance of the panels though. Can't imagine it would but it's still magic to me how those things work.

gcrank1
Member
# Posted: 4 Mar 2021 10:06
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I caution restraint before applying anything

ICC
Member
# Posted: 4 Mar 2021 10:17 - Edited by: ICC
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Try it on one panel, you have many. Or one half of one panel for a real side-by-side test

paulz
Member
# Posted: 4 Mar 2021 10:36
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It would be difficult to detect on one panel out of 15. I do have those two 100 watt panels charging my tractor batteries, I could try those with an ammeter inline.

Incidentally, I splurged the other day and bought a non-contact DVM, $100, hoping I could measure panel or array voltage easily to see what's doing what. No luck so far. It's supposed to measure both DC voltage and amperage but I have gotten nothing either at the panel wiring nor the SCC to battery. I did put it on my truck, started it up and turned on the lights and heater, got 2 amps at the battery cable.

It might be just too low for this thing, or it might need bare wire to read (although the Donk thing doesn't). Going to play around a little more and hope to get something out of it.

Here is what I got:
https://www.harborfreight.com/cm1000a-1000a-t-rms-acdc-clamp-meter-64017.html

Owners Manual:
https://manuals.harborfreight.com/manuals/64000-64999/64017.pdf
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ICC
Member
# Posted: 4 Mar 2021 12:19 - Edited by: ICC
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The clamp part of a clamp meter only reads amps, at least that has been the case for any I have used. It may be able to sense the presence of voltage in a non-contact method but I don't understand how it could read the actual voltage.

paulz
Member
# Posted: 4 Mar 2021 12:23
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Yes it says to read volts you hold the wire to the probe at the top of the clamp, on the outside. Maybe that's AC only. But I'm still getting no amps on the solar, and on the car I think it must have been charging more than 2 amps.

Did a little searching, they do make a product to put on solar panels, and also some have experimented with Rainx etc.. I haven't read all the posts yet but here is one product:

http://shieldsolarpanels.com/

ICC
Member
# Posted: 4 Mar 2021 14:03
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Quoting: paulz
It would be difficult to detect on one panel out of 15.


I was just thinking of a visual test. Treat one panel and after a month or so see if you can see any difference in the amount of dirt that is on the treated panel. Or the half panel. I don't think anyone could argue that dirt on a panel does not matter. Anything that blocks sunlight from striking the silicon layer cuts output. If the treated panels remain cleaner, then maybe it could be worth the effort and cost to treat them. Maybe in a marginal production area likeyours.

Theory states that PV panels at a higher altitude produce more power than those at sea level, because of there being less atmosphere for the sunlight to travel through. Two studies I have read do seem to back that up, although there also may have been other factors like temperature influencing the data. But it does make sense that a clean panel could produce more power.

I have never worried about it as my systems work fine the way they are and I don't want the extra work.

paulz
Member
# Posted: 4 Mar 2021 19:58
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Quoting: ICC
was just thinking of a visual test. Treat one panel and after a month or so see if you can see any difference in the amount of dirt that is on the treated panel.


Oh, yeah I can do that, and it's supposed to rain Saturday. Stand by.

I was just concerned that it may somehow inhibit how the panels absorb light.

gcrank1
Member
# Posted: 5 Mar 2021 20:42
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Ya know, looking at the thread title again it comes to mind that you may actually be 'General Solar' here

Steve_S
Member
# Posted: 6 Mar 2021 09:49
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From my understanding it is unwise to put any coatings on solar glass. Also to Never Ever use any form of chemical cleaning agent. If you look at the glass it is not smooth and a bit unusual, this allows for air to get under ice formed on the glass to allow for it to slide off. This also helps when it rains to channel the water in such a way that the entire glass surface is evenly rinsed. Just look at the panels in a light drizzle or rain and see how the entire panel is being rinsed as the texture encourages sheeting.

Plain Clear Water is the best thing to clean & rinse panels. Never use any form of abrasive material or chemicals, most especially acidic cleaners.

paulz
Member
# Posted: 6 Mar 2021 10:59
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Are my panels actually glass? The way they've taken a bending and beating moving them around I thought they were some kind of plastic.

Anyway yesterday I put my hi falootin ceramic car wax on one of these small panels, before it rained last night. This morning I can't see any difference in water retention. I'm surprised, as like my truck, it's much smoother to run a hand over compared to the other panel.

Oh well, saves me a bunch of work..
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paulz
Member
# Posted: 6 Mar 2021 12:45 - Edited by: paulz
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Darn, looks like my Renogy Rover CC bit the dust. I was outside the cabin when my wife yelled SMOKE! Gone when I got there but no charge out of it. Now it's just displaying gibberish.

I checked and the PV voltage was just over 100, which is odd because it usually shows 50-70. I really think the rain does something.. It's supposed to have PV over voltage protection and shut down until voltage drops. So maybe that was the problem, or maybe it's true about Renogy..

Anyway time for a new CC. Just when things were starting to look promising. At least I was here when it happened and no fire.

paulz
Member
# Posted: 8 Mar 2021 09:23 - Edited by: paulz
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Quoting: gcrank1
Ya know, looking at the thread title again it comes to mind that you may actually be 'General Solar' here


Salute when you say that!

I took the smoked Renogy CC apart, wasn't hard to find the burnt dingus. I would try getting a new one and soldering it in if I could figure out what it is. Any idea? Looks just like the other dinguses
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paulz
Member
# Posted: 8 Mar 2021 11:10 - Edited by: paulz
Reply 


So, digging a little deeper, the one next to the one I circled is cooked too. Can't read the numbers but I pulled up one of the others that looks the same, it's a MOSFET 100B202, and they are about a dollar. The question is would they be the same as the ones that fried?

gcrank1
Member
# Posted: 8 Mar 2021 11:18
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Isnt the bigger question,'why did they fry?'

paulz
Member
# Posted: 8 Mar 2021 12:01
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Yes, I'm waiting...

Might have overheated. About a week ago I noticed a slight smell, wasn't sure if it was the CC, the batteries, a connection. Nothing felt even warm. The CC was screwed to the sheathing between two studs (awaiting my paneling project, which is coming along) with a block about a foot above, in a corner of the cabin. I took it down and had it just laying on the end table when it fried yesterday. In open air but the fins are on the bottom so air couldn't rise vertically from them.

Still, it has never shown more than a 5 amp charge, and it's a 30 amper. As I said, for some odd reason the panel voltage was tick over 100 (max spec) when I checked it, unusual because it's usually only about 90. Something caused a spike after the rain. And still again, according to the manual it's supposed to have over panel voltage protection and shut itself down.

paulz
Member
# Posted: 16 Mar 2021 14:44 - Edited by: paulz
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New Epever SCC en-route..

I've put some panels on my roof for testing, which gets less sun than the deck but overall probably not a big dif. Actually not bad since my ridge points almost directly north.

What are the options for attaching to asphalt shingles? I guess putting screws through into the sheathing is OK? I was thinking maybe I could make 2x4 frames, screwed to each other at the ridge but not attached to the roof, and screw the panels to them? I get almost no wind, no snow..
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20210316_111046_resi.jpg


gcrank1
Member
# Posted: 17 Mar 2021 13:11
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Ive gone with ground mounted because I hate the thought of holes in my roof and Im getting too wobbly to be messing about going up/down a ladder, much less being on a roof (Im learning my limitations now).
But, thinkin on it, if I were to roof mount I dont think 2x4s would be needed, 2x3 (1.5 x 2.5 nom.) would do to be good backers and provide the couple inches of airflow between panel and roof. At todays lumber prices Im not as cavalier about oversizing as I once was.
Alum would be nice if youve scrounged enough to do it.
If possible Id want to lag bolt those to rafters and use a very good sealant at the holes. Shouldnt be any worse than the old roof mounted antenna tripod Ive had up for 35 years.
Are you going to ground wire the array?

paulz
Member
# Posted: 17 Mar 2021 15:14
Reply 


Thanks g. Ha, I have been up and down that roof 50 times in the last 3 days, I know what you mean. Including pushing those panels up a ladder over my head while climbing it. But I'm limited for ground space. You can see the other panels cantilevered off the deck in that photo. I might have room on the roof for those 9 panels if I cram, but they are in a better sun spot where they are, just ugly. Taking it a bit at a time. The good news is we just spent 3 nights and with about a 5 amp charge during the day it just about keeps up with out needs. Sure is nice not dragging batteries back to the grid for charging.

What is the necessity for air space under the panels? Hope it's not heat, 'cause they are sitting right on the shingles right now, hooked up, and I'm back at my city house.

Yeah I'll ground wire it when I get them mounted and situated.

gcrank1
Member
# Posted: 17 Mar 2021 16:24
Reply 


Yep, air flow for the heat, you dont want it trapped under there in the Hot Summer Sun (which, with all your shade may not be that big a deal right now).

ICC
Member
# Posted: 17 Mar 2021 18:12 - Edited by: ICC
Reply 


Quoting: paulz
What is the necessity for air space under the panels?

Yep. Heat. Three problems... 1= the shingles will be baked/cooked. 2= The panels will be much hotter and hot panels have reduced power output. 3= studies show that hotter panels fail more and earlier than cooler panels

The commercially available panel standoffs for a roof mount system are often 4 inches tall with 6 inch standoffs being very available. We want air to be able to move freely to help cool the panels. Yet another reason to prefer ground mounts when space is available.

paulz
Member
# Posted: 18 Mar 2021 10:55
Reply 


OK, air space it is. I remembered I still have about 100' of half circle 4" PVC pipe left over from my roof gutters. Can probably put that to good use.

Cool and rainy for the next few days, and of course shaded, so I'm sure they'll be OK till I get it done.

Thanks guys.
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paulz
Member
# Posted: 21 Mar 2021 09:58
Reply 


Another day, another obstacle..apparently I have gone from not enough juice to too much.

Got to the cabin yesterday, battery voltage was 14.4. Turned on the Wifi router and it went haywire. It normally runs off 110ac and a 12v wall wort. Didn't seem to bother anything else.

The lights all still came on but that was it. Tried connecting it to a stand alone battery, still no go. I got a hold of tech support (they own the box, I think), they got it working again over the line, said they did a factory reset. Still on the stand alone battery now, which is how I am able to send this post.

I'm thinking it's too much voltage for the router? Is there a 12v regulator I can put in at my batteries for all the 12v stuff (water pump, lights, fans..)? I don't suppose the load terminals of the SCC are any different than battery voltage? Don't see anything in the manual. Or I could run the router off an inverter and the wall wort but I don't have a pure sine inverter yet..

paulz
Member
# Posted: 4 Apr 2021 20:41
Reply 


I mounted the panels on my roof onto the aluminum racks they came with. Only about 3 inches space but I have yet to feel them even warm. I have room that I could move most of the panels around my deck up on the roof but might not be a good idea, better to have them scattered for sun.

My wifi router has been fine since it hiccuped, chalking it up to electronic gremlins..

Gotta say it sure is satisfying making and sustaining my own power. No more dragging batteries around for charging. It's even keeping up with daily use, not requiring off time to recharge the batteries.
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20210404_165245_resi.jpg


gcrank1
Member
# Posted: 4 Apr 2021 21:18
Reply 


My system often reads 14.4 during peak of day on bulk, but no wifi router to hiccup. Once I turn stuff on it has been dropping to 12.8-12.9ish (agm bat full charge level) after a couple hours though as I get past peak sun (for me that is after 1pm; trees...) it keeps falling. Ive been suspecting one of the aged bat-bank of the remaining 2 of the original 4 has failed. I disconnected one at a time to let sit for a couple hours and see if the top-charge fell off badly but neither did....hmmm.
So yesterday I borrowed a friends load tester, what a tool!; right away it showed me one bat is junk (no residual 'beans') so it was pulling down my bank. With it out of the loop Im expecting the last remaining 9yr old battery to do somewhat better though I also expect I will finally kill it off too. Good long run though, hey.
I now am convinced that anybody with a lead acid battery bank needs to have a load tester available; dont know if one plays well with lfp?

Daaaaaaaan
Member
# Posted: 5 Apr 2021 13:16
Reply 


paulz: I doubt 14.4V is an issue for the router. It probably drops everything down to 3.3V inside. 12V LED lights might run a little brighter with reduced lifespan, but they're cheap, I'd just deal with it unless you see them burning out often. RV water pumps should be fine, but a truly 12V pump might run a little fast at 14.4V. Same with the fans.

Having said all that, I'll keep what I initially wrote:

"Is there a 12v regulator I can put in at my batteries for all the 12v stuff (water pump, lights, fans..)?"

Efficiently, or cheaply and inefficiently?

Question is, how *low* can your voltage get and what will the router still be happy with? You can drop voltage 0.3V at a time with 1N4001, 1N4002, 1N4003, 1N4004, 1N4005, 1N4006 or 1N4007 diodes. 4 of those and you have a fixed 1.2V voltage drop. They're pennies/piece and will generate a touch of heat. But if your batteries are at 12V, then you're getting 10.8V. Your router might still be okay. It probably drops everything to 5V anyway internally.

Still inefficiently, but more precisely, and again only for small loads like a router, a linear regulator will drop voltages to a specific voltage. But needs to have a minimum drop of about 1V (or 0.5V for the low-dropout variety). For a 12V low-drop regulator, you could use an LM2940T-12

There are "switching regulators" that will give you 95% efficient conversion, here's a fancy one:

https://www.ebay.ca/itm/LCD-Display-Adjustable-Voltage-Regulator-Step-Down-DC-Buck-Mo dule-5v-9v-12v-2A/124213179205

Here's a "24V" to 12V, but should happily accept 13V or above:

https://www.ebay.ca/itm/24V-Step-Down-to-12V-5A-60W-DC-Waterproof-Converter-Voltage-R educer-Regulator/254460906221

But these are only step-down. If you feed them 12V, you might get 11.5V out.

"I don't suppose the load terminals of the SCC are any different than battery voltage?"

Should be close enough since the wires are probably thick. What might matter more is the wiring to your devices:

12V could drop a lot depending on distance between load and batteries, and the wire thickness. For a router using 0.5amp under usual conditions, the voltage drop won't be much over 10'. But this drop is why the device has a 12V wall wart when it converts it again to like 3.3V inside: Running a couple amps at 3.3V will decay a lot over 10'.

"Or I could run the router off an inverter and the wall wort but I don't have a pure sine inverter yet"

Wall worts will work just fine with any inverter. Especially the newer light-weight ones (not the 1lb ones from the 90s). It's only electric motors and maybe fluorescent ballasts that really care about sine wave.

Daaaaaaaan
Member
# Posted: 5 Apr 2021 13:19
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Quoting: paulz


20210404_165245_resi.jpg

Nice looking place. If you have enough juice, then you have enough juice. With that, the panels on the deck might take a dive for efficiency with the constant shadowing from the railing.

paulz
Member
# Posted: 6 Apr 2021 09:41 - Edited by: paulz
Reply 


Thanks Dan (for short). Since that one router episode it has been fine, but, I haven't seen voltage above 14 when I get to the cabin (twice a week about), seems to be 13.4-13.6. I know the controller max charge is 14.6, but when and why it charges that much I don't understand. If it goes that high again I'll see how the router handles it. I will keep the regulator info in mind if the issue pops up again.

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