diy solar

diy solar

Brown bear destroyed our yurt powered by Yeti 3000, so I'm designing solar for a cabin & a bit lost

No, that's not the case at all. That would only apply if you're trying to charge using all of your panels in parallel. No one does this.

This is where putting panels in series comes in. By putting them in series, the total VOC output of the string is multiplied by the number of panels in the string and the string voltage becomes high enough to be able to charge the lower voltage bank.
 
Here is a great video that shows our months of darkness given the terrain and trees to the east and south. Sun Seeker app on iPhone works great!

We can cut some of these trees to the southeast and get a little sun during sunrise but we'll have a solid three months of no sun for sure. Maybe some sun bouncing off a cloud deck, but mostly darkness. Our panels will be about 15-20 feet higher than I'm filming so that should help a little.


You have a diesel for those months?
 
You have a diesel for those months?
We will have a propane powered generator for those months. But we will also be installing a satellite solar array somewhere on the property that is positioned for those months, then bury a cable back to the cabin. We also have solar on a different part of the property where our garden is and it gets sun year round and will charge some goal zero batteries that we can swap out in the cabin as required. Between these three options this should work out pretty well I think. I'm hoping the satellite solar in a spot that gets good sun in the winter, elevated with maybe just 800W of panels or so, straight up and down so no snow on them will do the trick. I think there might be a spot relatively close to the cabin where I can elevate just those panels and make it work without cutting down lots of forest.
 
I think based on what Sun Seeker is showing, that the vertical panels in my plan aren't all that useful. So I think I will put those panels on the upper roof instead which should make installation more simple. But I will put some kind of heating element on the panels to try to melt snow that lands on the panels.
 
It's going to be a metal roof and I've seen somewhere there is a solar rack that "pinches" onto the metal ridges to hold the rack on the roof without having to penetrate the metal. Anybody have any experience with a rack like that by chance?
 
So now that we have a cabin, we're getting ready to order our solar equipment so we can install it this spring. But we've decided not to install on the cabin in our less than stellar location but rather to make a ground mount system 500 feet away from the cabin on a spot that will get 4 hours of direct sun on 21 December on a sunny day (rather than on our cabin which would not get any direct sun for three months).

One question I have is with a Victron 250/100 SCC, if my panels supply more than 100 amps to the SCC that should be okay right? The SCC will just not be able to charge the battery with more than 100 amps so some of the amps might be wasted, but there won't be a safety issue?
 
One question I have is with a Victron 250/100 SCC, if my panels supply more than 100 amps to the SCC that should be okay right? The SCC will just not be able to charge the battery with more than 100 amps so some of the amps might be wasted, but there won't be a safety issue?
There are very clear limits to how you can overpanel a Victron controller, and one of them is max Isc.
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What system voltage are you going for here, and what size array?
 
Try looking at other deterrents too... I have experience to keep deer out of gardens, A/ tie a fish line in the air around head height across likely bear paths, they won't see it and they will get a scary surprise from a strong invisible fishline suddenly on them... B/ I use a mix of strong artifical scents, mix white sprite, engine cleaner, bacon, vinegar, turpentine, light oil perhaps for the top, and attach bottles to trees around the place with a bit of a gap to let the solvents escape while keeping the rain away.
 
There are very clear limits to how you can overpanel a Victron controller, and one of them is max Isc.
View attachment 78935

What system voltage are you going for here, and what size array?
Thank you.

I think we're going to go with an 10.6KW array hooked into a Victron 450/200 (just learned about this larger SCC). Two strings of 6s2p of LG4402T-E6 bifacial panels.

I'm still trying to figure out the specs of that panel because I don't understand the three sets of numbers (STC, BI100, and BI200) but I think the 450/200 will be plenty big enough although it's possible it will get more amps that it can use to charge the batteries (10.6KW / 48V = more than 200 amps). Just using the STC numbers, the VOC is 46.0 and the ISC is 9.01.

So the VOC would be 46.0 * 6 * 1.23 (temp correction) = 340 which is under the 450 by a good margin and the ISC would be 9.01 * 2 = 19 (the max is 20A per tracker in the 450/200 and it has 4 tracker inputs).

These panels apparently can produce more power than the 440W given they're bifaicial and I'm not quite sure how to account for that in sizing the SCC.
 
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You're going to need hefty wiring for a 500ft run that can do 30-40A, but I guess you've already thought about that ;)
 
You're going to need hefty wiring for a 500ft run that can do 30-40A, but I guess you've already thought about that ;)
Yeah I think either 1/0 or 2/0 wire based on some calculator I used before (but have already forgotten how to use). Not cheap. But I need to figure out the wiring to be certain since I'm still pretty foggy on how to calculate the wire size.
 
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I would be very surprised if you have to go that thick. I did some quick cable math and 2AWG will only have a few percent voltage drop. Which is fine in your case. That voltage drop is only really noticeable during Pmax anyway.
 
I would be very surprised if you have to go that thick. I did some quick cable math and 2AWG will only have a few percent voltage drop. Which is fine in your case. That voltage drop is only really noticeable during Pmax anyway.
I have no idea how it works in case that isn't abundantly clear. I'm still trying to ensure the strings of panels will work with the SCC although I think I've got that mostly nailed down.

So I've got a bunch of PV providing power to the huge SCC. Then I think that connects to a Victron Multiplus II which will charge the 48V battery bank. All those components will be close to each other. But what sends power from what, over the 500 foot wire, to get to my breaker box at the cabin......I have no idea. I assume it will be the Multiplus II that will do that. And I have no idea what volts and amps it will send when it does it.

Several months ago when I looked into this I thought I had a weak grasp. Now that I've sat back down to look at things, I realize I was being too optimistic!
 
Thanks to all the great info presented by all of you here, we have changed our plan considerably. It should produce more power and be cheaper, fingers crossed.

1. We're going to install a ground mount 500 feet away from the cabin rather than at the cabin at different angles

2. We're going to create a root cellar underground for our batteries and the other components to keep the batteries warm in the winter

3. We're going to use a 48V battery bank

So I've created a new thread to discuss the new system since it has changed so much from the OP.
 
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