Hello

[Katespak]

I am an Unknowledgeable newcomer from Southern Ohio looking to learn.

I am having a stick-built garden shed installed in my backyard. It is only 6’x8’, but has a high-pitched roof (18/12). I would like to install a budget-friendly solar system to run LED growlights, an outdoor LED light and be able to use power tools from time to time. Looking for something simple to install myself. The shed will face east with a solid wall on the south side. The southern sunlight is scorching here in the summer, but gloomy quite a bit during the winter. Also, any input into making the system fit less noticably into the design would be welcome. (Any interior designer/architects here?) All input would be welcome. Thanks so much! Kate

 

[svetz]

Hi Kate, Welcome to the forums!

For solar, the place to start is an Energy Audit to figure out how much power you'll need. Everything else flows from that.

Here are some other links to get you started, but please feel free to ask questions.

• From the FAQ:
  • How many panels do I need?
  • How big of an inverter should I get?
  • Do I need Batteries and if so how many?
  • Will a modified sine wave Inverter work for me?
  • What tilt angle should I use?
• How much power do my devices consume?
• How much Solar Energy is there where I live?
• How to figure out how much Solar and inverter wattage is needed to charge a battery
• What does it mean to have solar panels in parallel and series?
• Figuring out how many panels in series and parallel based on your MPPT

 

[45North]

I am an Unknowledgeable newcomer from Southern Ohio looking to learn.

I am having a stick-built garden shed installed in my backyard. It is only 6’x8’, but has a high-pitched roof (18/12). I would like to install a budget-friendly solar system to run LED growlights, an outdoor LED light and be able to use power tools from time to time. Looking for something simple to install myself. The shed will face east with a solid wall on the south side. The southern sunlight is scorching here in the summer, but gloomy quite a bit during the winter. Also, any input into making the system fit less noticably into the design would be welcome. (Any interior designer/architects here?) All input would be welcome. Thanks so much! Kate

Or you could do it the other way around:
Since your shed is quite small 6 x 8, you may want to start off by assuming you'll need as many panels that will fit on the roof.
After that, choose some batteries and charge controller to match.
The amount of stuff you can power (lights and tools) would appear to be limited by the constraints of your roof size, panel size and budget.
That might be enough to get you started. Beyond that, if you want to power more stuff you'll have to upsize your panels and everything else.

 

[svetz]

... start off by assuming...

The problem with assumptions is that it can lead to a costly rabbit hole of purchasing gear only to find it won't do what you need. And, there's zero need to make any assumptions, it's not hard to figure out.

Let's walk through some of the math to get you going. Change all the example numbers below for your real numbers / situations

How many panels can I fit on my roof?

Is the roof flat as shown to the right, or more resemble an "A"? We'll assume an "A" shape. ...6’x8’, but has a high-pitched roof (18/12)... At 18/12 pitch for every 12" of run (b) there is 18" of rise (a leg). Assuming an "A" shape, then the roof centerline is 3' in, so 3x18/12 = 4.5'. If the roof is flat use 6 instead of 3.

From trig, the two "legs" are 3' and 4.5', and the hypotenuse (length of the east side roof) is a^2 +b^2 = c^2, so sqrt(3^2 + 4.5^2) = 5.4' (64").
So, the east facing roof area would be 8' x 64" or 96" x 64".

...simple to install myself... Panels come in different sizes, but typically a 335W panel runs about 62.6 x 41.5. So, the good news is an "A" style roof on one side would fit two, the bad news is they weigh about 55 lbs, so that makes "simple to install myself" a bit more challenging. Two 335W panels at STC would provide 2 x 335 = 670W. STC are test conditions, you won't actually see that much power from the panels, but more on that later. 200W panels run about 52" x 39" and weigh 35 lbs, but you could only still fit two for 400W. 100W are typically around 40.2" x 26.4 and weigh 18 lbs,, but you could fit 4 for 400W To the right are a few example layouts. Only half the roof is shown for an "A frame" style roof, if you use the west side too you can double up.

...making the system fit less noticeably into the design...
There are solar tiles designed to look like shingles, but they're the most costly option. The good news is they're very small, easy to install, and would allow you to maximize the maximum power.


How much power do you need?

I would like to install a budget-friendly solar system to run LED growlights, an outdoor LED light and be able to use power tools from time to time.

Forgetting the power tools, a single little 2' square LED Grow lite consumes 115 W. Let's say you just want to augment natural light for 3 hours a day. So, for this model of grow light you'd need to generate 115 Watts x 3 hours = 345 watt-hours/day. The energy audit will have you get the amount for your selected devices for actual time. If you needed 4 such lights all for 3 hours per day that would be 4 x 345W = 1380Wh/d.


How much power from the panels?

Since you live in Ohio let's assume a big city like Cinci and lookup the insolation for values for a steep roof for winter. From the table copied to the right, for December you could on average expect and insolation of 2.11. So, for four 100 watt panels you might expect: 4 panels x 100W x 2.11 = 844 Wh/d A program like PVWatts can take local weather into consideration and give you better numbers. That 844Wh/d is what the panels generate. You need to convert that via an MPPT, store it into a battery for when you need it, and then run it though an inverter (although the inverter isn't needed if you can get grow lights that operate at 12V DC). Each step along the way loses power by the efficiency of the equipment. With good quality gear that's usually in the 90-98% range, but let's assume 90% for each, then 844 x .9 x .9 x .9 = 615Wh.

Hope that helps!