On the utility of multiple backups

Alternative energy sources
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The usual. As I have two large solar PV systems here, and my lab assistant just put one in, and others are interested in things like this, here's where that stuff goes. This is mostly for things that work now, not "gee someday a fusor will do this" -- we know that, but it's not someday yet.
The hope is to save anyone embarking on this sort of thing a lot of wasted time and money, as at least I have been off the grid since 1980 and have had a lot of practice (and made mistakes you won't have to).

On the utility of multiple backups

Postby Doug Coulter » Fri Jan 18, 2013 12:46 pm

http://gm-volt.com/forum/showthread.php ... wered-post!

I had to use my CAR to keep my house going! I guess it's only fair to have the KWH flowing the other way once in awhile. Glad I had this as an additional backup, as my main backup failed - at just the crucial moment.

I will add some more data and pix related to the above link here as I get and process them. We really got a surprise "microburst" snowstorm last night, everything failed at once, almost - except the very handy Volt with the inverter hack, or I'd not be able to make this post at all! Full sun as I have this AM doesn't do squat for panels covered with a foot of snow and ice (eg can't really just scrape them off and let the sun do the rest, it's really stuck on there).

Some pix of this. It's supposed to get down in the teens tonight, and I still have a vulnerable water system for the toilet - so today is going to be quite busy with fixing all this to a nearly back to normal state. As usual, click the pic for a larger version
Somewhere along the line (I fell a few times trying to get snow off a rack of panels) I lost my lens cap and didn't realize I'd also watered the lens, oops.

VoltSavior.jpg
The last backup layer - it worked when all others failed.

snowpanels.jpg
Sun, but no juice! Ice under snow - this is going to be one heck of a cleanup job.

TreeSnowWest.jpg
Thick enough to down some trees, but pretty.

SnowSouth.jpg
More snow laden trees. This was ice, then snow.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
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Re: On the utility of multiple backups

Postby chrismb » Fri Jan 18, 2013 3:01 pm

When it's over, perhaps you should install some 'storm covers' that you can pull over the panels if you're expecting bad weather.

M'be you could even try setting up a string of irrigation hoses that run just along the top of the panels, and when you need to clear this stuff you pump a little warm water through them. A gentle flow of warm water should undermine the base layer and it'll slide off.

Just a though!?
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Re: On the utility of multiple backups

Postby Doug Coulter » Fri Jan 18, 2013 4:40 pm

The water idea is probably a good one if I don't also have all my water frozen at the time ((often the case) - or I had an unlimited supply, not the case ever - I usually have about 100 gallons to work with, total, and use only about 2 a day normally - two teas and one flush, basically, showers only if I have surplus water collected. That's quite a few tons of snow and ice, I don't think the pulloff cover game would work - you'd be killed as it fell on you. I've decided not to go up on an icy roof to do things from above anymore.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
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Re: On the utility of multiple backups

Postby Joe Jarski » Fri Jan 18, 2013 5:51 pm

The snow is sticking to the nearly vertical panels pretty well! I'm gonna have to ponder this a little for my own system.

At least it's clear and sunny! ;)
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Re: On the utility of multiple backups

Postby chrismb » Fri Jan 18, 2013 6:54 pm

hmm.. maybe there is some sort of option where you can heat the panel from underneath, electrically.

In fact - can [or would it be a good idea if it could be designed and invented that] a solar panel be safely heated by applying a reverse current? That way, the immediate layer would melt in a, hopefully, uniform way and get the snow and ice off that way?

.. just brainstorming here...
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Re: On the utility of multiple backups

Postby Doug Coulter » Fri Jan 18, 2013 7:36 pm

Actually, you could do that if you had a source of enough power. Solar panels are run in a forward bias mode - so all you'd have to do is put the same polarity in as normally comes out, but at a higher (and current limited!) voltage. BillF sent me an idea in an email - how about something really hydrophobic, like RainX? Or maybe there's something better like that. The glass on these panels (no matter who made them) is a bit "wiggly" for whatever reason, it's not super flat and smooth. That's why stuff can stick to it when it's almost vertical. But this was just a real nasty one - even my smooth windows had snow stuck to them, and they are vertical.

Edit: Got the regular generator going again today - sitting overnight with its panels off next to the woodstove did the trick. I put it back out there, and it self-cleared about a 6' radius around it with waste heat. Hmmm...
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
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Re: On the utility of multiple backups

Postby Doug Coulter » Sun Jan 20, 2013 12:51 pm

Post mortem:

Well, the Honda ran after drying overnight, so the immediate emergency was over pretty quick.
Next day, the near vertical panels had all nearly cleared themselves. Once that had happened, warm air from the lower ones quickly loosened and helped clear the ones above, though a few parts of them were resistant to getting fully cleared - that gap between the steep and shallow got clogged up. I actually *did* go up there with a broom, and with a swift kick on the snow on the horizontal ones, got it sliding fast enough to fully clear. Except at the very bottom.

Joe, I'd suggest leaving some room at the bottom of any panels you put up, since that's where the snow is going at some point.
BottomSnow.jpg
Now, if I could only find my shovel, but I left it out - it's under some snow somewhere.


Things cleared up pretty quick in the sun - all you really have to do is get a little of a panel clear and the sun will do the rest. It doesn't have to be above freezing, the sun's still pretty powerful when hitting something "black" and these are real thermally conductive.
Top.jpg
All clear now, and the snow/slush/refreeze pack on the roof actually made it safer than dry.


And of course, the bottom line, the Volt charger showing full operation before noon today (Sunday).
Charging.jpg
The green lights are good - 3kw going to the car yet keeping the house batteries up too.



A big hat tip to all the emergency guys. I went out in the truck this AM, and must have seen over 60 trees down across the road they'd already cut lanes through - this was a 10 year event (at least), with little warning. The other two I've experienced here in nearly 40 years, we were warned, and it took 3 days to deposit the 6' of snow we got - nice light fluffy stuff that time, but we were also socked in then. When it gets that serious, they have to use trucks and loaders, since there is just no place to scrape it to, and that takes time.

The power is out for miles around me, except for me - I checked and all neighbors the backup generators are running, and there's one going at every fiber->dsl drop box for the phone companies. Pine trees were most affected, and some are still bent double under the weight around here. If I wanted some already on the ground pine wood, all I'd have to do is take the truck and saw to it - I saw enough to fill about 10-20 8 ton farm trucks just lying along the roads, or partly in them. But I hate cutting pine and it takes forever to cure, while being sticky, so I'll let someone else be that hero.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
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Re: On the utility of multiple backups

Postby solar_dave » Mon Jan 21, 2013 9:04 pm

Glad to see you are out of the red zone and that Volt is getting a taste of the sun!
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http://phx-solar.no-ip.info:8081/Footprints.html
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Re: On the utility of multiple backups

Postby Doug Coulter » Thu Jan 24, 2013 6:39 pm

Yeah, it's sweet. Now to figure out a way to make the snow come off the panels faster next time, and learn my doggone lesson about having extra hot spares. While the Volt system works - and well - it could be better itself, and I will look into making it more efficient. Sure saved my bacon that time, so I'm not complaining.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
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