Solar shed from scratch...

willo

Solar Addict
Joined
Apr 8, 2020
Messages
388
I'm plotting a new shed. I'm thinking of making it a full on solar shed. Here's what I'm thinking.

A custom 14x8 shed with a 12 foot interior ceiling height, with a 35 degree roof. Lowest point being 8ft from the ground.
For the diagram, I added a 1 foot overhang to each side, but could add more. The key is to have a 120sq ft shed for building code.

With this, I can fit 18 250w panels from santan - for a 4.5kw solar array at a cost of around 1k.
I also get a handy shed.
I could run 2x6 and only have 12 panels for 3kw, maybe 14 to get up to 3.5kw with a wider config. I need to go figure out the optimal angle for this setup and work from there...

Some concerns - I can totally keep this shed off grid, I kinda like it. With a lean-to roof, I'm not sure if I need the roof peak setback that's required for larger buildings.
I like the angle setup, as the tall side would face the road, and I can install high windows for light without creeper drive-by neighbors.
I will likely add some supports for the lower end of the roof, in the form of angled buttress that run from the shed base to the overhang for support.

For now, I have a Tesla module I've been using in my camper, call it 3.5kwh of storage. I will probably upgrade this, plenty of lifepo4 deals running around out there.

Thoughts?


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willo

Solar Addict
Joined
Apr 8, 2020
Messages
388
Here's my preferred design. It's a little funky, but designed to push the boundary's of my county's building code.
1) 120sq foot base - this is 8x14 = 112sq foot.
2) The overhang on the rear is three feet off the ground, so it gives me a huge working countertop and makes the interior more like 11x14.
3) The 'Solar roof' provides a 16x14ft surface for panels. Not as huge as the version above but pretty usable.
4) panel options - if I stay inside the lines, I can deploy 8 panels, if I add a side overhang or extend my solar roof to one side, I can fit 12 panels.
8x250w = 2000w (400+ship)
12x250 = 3000w (600+ship)
If I go with 370w panels, I can fit 12 without getting weird(er) so
12x370 = 4440w. - ($2kish).
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willo

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Apr 8, 2020
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388
What are you doing with the power? What kind of Controller/Inverter/batteries? Wood is hella expensive right now in the USA, so keep that in mind in your design.
Some system options:
Plan for 24v battery, can use my tesla until I buy more Lifepo4s

BMS - SBMS0, I use it elsewhere.

Solar controllers:
2x Victron 100/50 controllers (I already own one) each with a string of 6x 250w panels, probably just paralleled.
OR
DSSR0 with the SBMS0.

Inverter:
A big reason for this build is to offset my home office energy consumption. I will probably spend up and get another Victron Multiplus. I love the one in my camper, and yeah it's expensive but so worth it.

Also, RE: Wood - I know. It's insane. I'm working on building a house... :/
I'm hoping that prices will drop as things open up again - COVID basically meant a huge surge in home projects and shortages in shipping.
 

iamrich

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Joined
Dec 17, 2020
Messages
767
Location
Elgin, Texas
Are you going to work in this shed or pipe the energy from the shed to the house? I love the 250w Trina panels, so I would get as many as you can fit.
 

45North

Let it shine!
Joined
Jan 2, 2020
Messages
448
Location
Canada
Looks good!
The 35 deg slope on the roof will be a good year-round compromise assuming you are about 35 deg from the equator.
 

willo

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Apr 8, 2020
Messages
388
Looks good!
The 35 deg slope on the roof will be a good year-round compromise assuming you are about 35 deg from the equator.
around 39, 105.
I need the slope for the friggin snow. I'm up around 9,000ft in the mountains. (think between Golden and Boulder, but up over the mountains.

While I'm building the house, I'm pretty sure it'll be a small workshop. Once the house is built, It may become my office shed. My home office is over the detached garage now and I'm liking the separation of work/home. I figure the solar shed can act as a backup power generator for the house at a minimum.
For me the shed is an opportunity to test out the siding and roofing I want to use on the house. The solar bit will be a bonus and given energy costs, I can't see not installing some solar at this point.
 

iamrich

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Joined
Dec 17, 2020
Messages
767
Location
Elgin, Texas
The solar bit will be a bonus and given energy costs, I can't see not installing some solar at this point.
I think the best setup going right now is grid assist. I know with grid tie you can sell your power back, but grid assist lets you set up the house to run on solar/batteries with the short term reliability of the grid. At this point I am just hoping the quality of LiFePo will go up and the price will go down before I build my retirement house because I am likely going to have a solar farm at the rate I am going.
 

willo

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Apr 8, 2020
Messages
388
I'm not certain if I can deploy non-labelled panels for a grid tied solar.
I was amused by a giant page declaring that the power company is 'looking for' people who've got diy solar without permits.
Not saying I wouldn't get a permit for it, but I'd enjoy laughing at those people for giving me crap about an off-grid shed.
I suspect that I'd need to purchase the UL listed version of the multiplus for that as well. (more $)
 

iamrich

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Dec 17, 2020
Messages
767
Location
Elgin, Texas
With grid assist you are not backfeeding the grid, so in theory you shouldn't need a permit (of course I have not idea where you live or the rules there). The grid assist only allows you to feed grid AC into your system if you need it. You could also just use a generator to for assist using the same input. That is what I do with my LV2424. I don't have grid, but if needed I can push AC from my generator to feed the batteries. I am still toying with going 100% solar on the new house, but I will probably wuss out and just hook into the grid and then run a line to the garage to grid assist the LV2424 if needed. We'll see...
 

SolarPrep

Solar Enthusiast
Joined
Jul 15, 2021
Messages
132
willo: I love your idea. Just some suggestions for you to think about, based on my experience. I've been building for over 40 years, and have pretty much seen it all. We live in strange times with some bizarre constraints, which may mean adapting some ideas.

We used to live out in the same area you are talking about, and had to deal with extremely restrictive covenants. Here are some thoughts:
1. I always deal directly with the actual employee of what-ever city, country, whatever who is going to write the permits. I ask for their advice and help. For example I've lived places where the typical back yard shed is defined as 150 sf without a special permit. About half the places, it has been on the outside dimensions, but several, it wasn't specified. Others, it was use-able space.

2. Many jurisdictions have provisions to allow the employee to grant an exception, a variance, or a slight modification. Where I live now in the Midwest, they allow a local clerk to move the property line setback requirements by 10% with no interference from any board of adjustment. In our case, the setback on one side was 30' so 10% meant 3' of additional space for my proposed garage. Just for asking the question.

3. Many places strictly regulate how big overhangs are, and whether or not they count in the plan/permit for things like setbacks. Other places couldn't care less. You have to ask, or read the ordinance.

4. If you are out of town, and no one is looking over your shoulder it might make all this easier. But things like UL listing are basically controlled and written by the fire code people. I've found it to be nearly impossible to get a straight answer on most of those topics. In our area, they are now requiring any device that inverts electricity over 50 volts to be UL listed, if it is used in ANY FASHION in your building or home. Including an "off grid shed". I'm fighting this now, and just got referred to the State inspectors. They don't know the answers either. The funny part is the head inspector for our City just told me they are so swamped and understaffed they don't even have time to follow up on most calls. Some people would take that to mean that you should just go ahead and do what you want, and take the risk. Like putting in a Growatt unit that isn't UL. Personally I've had to battle insurance compnaies who don't want to pay legitimate claims, so I won't give them an excuse to deny my claim.

5. With your shed idea, consider a couple other techniques. One could be using SIP panels. Or build the entire thing out of concrete with ICF blocks. I've done several projects with them, and they are fun to work with. It takes a lot of prep work, but once you have that done, the rest is fast, and easy. I'm looking at doing a shed similar to yours right now, and I'm considering ICF. Wood is out of stock, high priced, and shit quality. When you pour ICF walls, put in some radiant PEX, and you are good to go. I was going to buy a 20' shipping container, but the price of those has gone through the roof. And they are a big target for complaints. You have to prepare a site for them, insulate them, deal with Corten, deal with the weird doors, etc. I think they are great, and if I lived in the country, I'd own one anyway. They do somethings really well, but they suck at so may others. Get a couple of buddies, think about doing ICF, and if you do, pay close attention to bracing. It is the key to success.

6. Your idea for the big overhangs is great. Get the most powerful panels you can buy, because they are all pretty cheap. You are going to have them for 25 years. Victron is great equipment, but it really irks me they don't get UL listing. I bought one anyway, and now I regret it.

Have fun with your project!
 
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