How Many Solar Panels Do I Need to Power a Shed?

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Solar panels are no longer just for roofs or RVs, as they are also used on pergolas, cabins and boats. So why not a shed? Sheds are common fixtures in many homes and can definitely benefit from renewable power. But how many solar panels will you need to run everything?

A 50W solar panel is enough to power a simple storage shed, while 2 x 250W solar panels are the minimum required if the shed serves as a home office. If the shed is used as a power tool workshop you need at least 4000W-5000W to run the equipment, lights and other devices.

Simple Shed Solar Power Requirements

A typical shed used for equipment storage will run with a 12V 50W solar panel. Using a 50W panel you can install a LED light or two to illuminate the place. You can opt for a 100W solar panel if you need more lights or want to add a few more equipment.

If the shed is used just for storage, you won’t need a lot of power, just enough to turn on the lights to find something or organize the shelves, or or add a solar powered fan for some cool air. Buy a solar panel kit and it comes with everything you need to set it up including the charge controller, adapter and mounting hardware.

Office Shed Solar Power Requirements

A shed that serves as a backyard office needs about 3000W-4000W of solar power. The chart below shows the typical equipment you will use in a home office. The biggest consumption will come from a portable heater or a fan.

ApplianceWatts
Desktop Computer100W-250W
Printer / Copier / Scanner100W-200W
Modem 10W-20W
LED Lights (4 x 10W)40W
Tablet / Phone Charger10W
Ceiling Fan50W-100W
Electric Heater2000W-3000W
Coffee Machine600W

Two 250W solar panels can produce 3000W with 4-5 hours of sunlight, but it might be insufficient during winter or cloudy skies. Unless you have a battery bank, it’s best to have more solar power on hand. For a shed backyard office, 2 x 300W solar panels should be the minimum.

Workshop Shed Solar Power Requirements

A typical power tools workshop will require at least 4000W-5000W. Three 200W solar panels can produce 3000W with 5 hours of sunlight, but that is under ideal weather. For power tool sheds it is best to have 3 x 250W or more solar panels depending on what projects you work on.

The following chart is for the most commonly used power tools. If you are going to work with a circular saw and other tools, you have to add extra solar panels or even a solar generator. Even then it you have to consider how long you have to consider the frequency of each tool’s usage.

A shed that serves as a workshop needs much more power than a backyard office. You have to list down all the power tools you will use along with their wattage. Add the total to the lights and other appliances you will use in the shed, plus account for starting / surge watts.

Power ToolRunning WattsStarting Watts
Circular Saw1400W4200W
Electric Drill600W900W
orbital Sander1200W2600W
Jigsaw300W300W
Miter Saw1800W1800W
Table Saw1800W2700W
Router600W1500W

Note that power tools have starting and running watts. Your solar panel must meet the starting watt requirement otherwise the system won’t run. The starting or surge watts lasts only a few seconds, after which it consumes less power (the running watts).

The chart also lists the usage per hour. It is unlikely that you will use all these tools for an hour. In most cases you will use the saw for a few minutes, stop and work on something else. After a while you use the drill for a few seconds, stop, resume and so on. For more on running power tools, check out our guide here.

So while the overall wattage is very high, in fact you will use less in actual work. But to be safe you should install more solar panels in case you need to use more equipment. This is not just for power tools but also well pumps and other high powered equipment.

It comes down to what power tools you use and how long you use them. If you only have a few tools then a small solar power system will do. If you are heavily into DIY, install a large solar array, a generator or both. Planning is the crucial element here.

Garden Shed Solar Power Requirements

A garden shed with manual tools only needs 100W or so for the lights. If you use power gardening tools, you need 2000W-4000W depending on what equipment you are using. Just like with power tools, these are the requirements for per hour use, so it is unlikely you will consume all of these watts.

Unless you decide to use all these tools at the same time, your solar power only needs to match the starting watts of every tool you will use simultaneously. If you will start up the electric cultivator without any other tool, 1500W+ or more solar power will suffice.

Gardening ToolRunning WattsStarting Watts
12″ 1.5 HP Chain Saw900W0W
Weed Cutter500W600W
1.3 HP Cultivator700W1400W
Hedge Trimmer450W600W
Electric Leaf Blower2500W0W
Electric Strimmer300W500W
Electric Mower1500W0W

This is similar to that of the power tool shed. The more tools you use the more solar power is required. Don’t just compute the tools’ total wattage, add the lighting and other stuff you will install.

How to Install Solar Panels on a Shed

Once you have determined what you will use the shed for, calculate how many watts you will need. There are three factors to consider.

  • The total energy consumption expressed in watts
  • The number of sunlight hours available
  • The available space on the shed roof

You should also make allowances because solar power production varies according to the time of day and season.

Suppose your shed workshop needs 3000W / 3kw. A 250W solar panel can produce up to 1500W with 6 sun hours (250 x 6 = 1500). Add another 250W and you have 3000W.

But this assumes the solar panels will be able to produce 250W per hour continuously. That is only going to happen in the most ideal weather. You should add 20% or so more power in case it rains or clouds pass by. Instead of 2 x 250W, get 2 x 300W solar panels for 3000W in 5 sun hours, or 3000W+ in 6 sun hours.

Aside from calculating the total energy consumption, calculate how you will use the power. How many will you be using at the same time? This is important particularly for power tools that have high surge watt requirements.

All of these calculations assume there are 4 to 6 hours of sun hours available. if it is winter, sunlight will be limited and so will solar panel production. You have to account for this either by adding more solar power or using a backup power like a generator.

Can the Shed Roof Support the Solar Panels?

Last but not the least, can you put the required number of solar panels on the shed roof? A 250W solar panel weighs about 40 pounds and measures 65 x 39 inches. How many of these can fit on the roof? Is the structural support capable of handling the weight?

You may have to do a balancing act between how much power you need and how much space is available on the shed rooftop. A ground mounted solar system is only possible if you have the land. Otherwise you have to make do with whatever is permissible on the roof.

After you have figured out the total wattage and tested the roof support capacity, you can buy a solar panel kit and install it. The kit will include all the necessary parts except the battery and inverter. You will need an inverter if you are going to use any AC device, and a battery if you want to work at night. Always follow the instructions and you should be ready in no time.

Do You Need Backup Power?

Yes, to be specific, a battery bank. Without a battery bank there is nowhere for the solar panel to store energy. Without any stored energy you won’t be able to work during the night or when there is a downpour.

How much battery power you need depends on how much you work during the night. If you spend most of your time working during the day, a battery equal or half of the total solar panel output may be enough. If it is winter and you spend hours in the shed, the backup battery should be equal to the total wattage.

Ideally if your shed has 4000W of solar power, your battery backup must be at least 350ah 12V, which is 4200W (V x aH W). If you are not sure which to buy, lithium, gel or AGM, here is a guide.

As for an inverter, the rule of thumb is it must be equal to the total watts plus 25%-50%. The total wattage must include the starting / surge watts requirement. Again, you may not need an inverter if all your tools are DC powered. In that case you can connect them directly to the solar panel.

The Benefits of Solar Powered Sheds

Is it worth all the trouble of putting up a solar panel on a shed? The answer is yes, because the benefits far outweigh the drawbacks, both short and long term.

  • Reduce energy costs. Setting up a home office at home can drive up your power bill. If you are already paying a huge amount to the utility company, investing in a solar power system for your shed will reduce your costs.
  • A good long term investment. solar panels increase the value of a property. Foreclosed properties with solar panels attract more buyers. If you ever decide to sell your home, a solar powered shed can entice more people.
  • Free energy. The power comes from the sun, so it is 100% free. Why pay for power when you can have it for no cost at all?
  • Easy to low maintenance. The most complicated part is the installation. After that you can rest easy. The solar panels may require cleaning every now and then. But mostly you can just leave it as is and the rain will do the cleaning for you.

Conclusion

The nice thing about a shed is it can be as simple or elaborate as you want. You can set it up for basic use or convert that shed into a full featured backyard office or workshop. Whichever you choose, solar power can help.