Solar Panels On Pergola - Solar Pergola & Patio Cover Design
Designing a DIY solar pergola
Can You Put Solar Panels On A Pergola?
A pergola is an structure with a roof and four or more pillars supporting it. In some circumstances it can be a great idea to use that extra roof space for mounting solar panels, either to supplement home energy usage or as an outdoor off-grid solar system.
The size and type of solar power system you install depends on what you want to do with it.
What this post covers:
- How many solar panels do you need?
- How much solar power can you get from your pergola roof area?
- Are solar panels too heavy to mount on a pergola?
- What type of solar panels are best for pergola mounting?
- What can the panels be used to power?
- What sort of controller and other equipment is need for a solar pergola?
Video – Solar Pergola Build and Design
DIY solar pergola design – Can you put solar panels on a pergola?
I’m going to fit solar panels on an existing pergola roof that’s pretty old, so I need to check that it can support solar panels at all!
The author’s DIY solar pergola roof
Solar panels on a pergola seems a great way to use that extra space. This particular pergola is currently used as a carport, which I also use for storing an inflatable kayak equipped with an electric motor.
I use a lithium iron phosphate battery for the electric kayak – I also have solar panels mounted on the kayak as well – I like solar!
In addition, I have a spare car battery and a lead-acid deep-cycle battery for home energy storage backup, so in total I have 3 big batteries.
The lead-acid are heavy so it make complete sense to leave them all in one place and charge them with solar panels on the pergola roof.
How many solar panels do you need?
If you have a particular task to perform, like recharging a number of batteries, then I would work this out from the battery capacity in watt-hours in this way:
- Battery capacity needing recharge at 50% discharge = 100Ah = 1200 watt-hours (Wh)
- A 100 watt solar panel generates on average 400Wh/day
- Number of solar panels needed = 1200/400Wh = 3 x 100 = 300 watts
So for building my solar charging station I need three 100 watt solar panels to make sure my batteries recharge in a day.
Is my pergola roof big enough?
Pergola Solar Panels – Sizes and Wattage
The average size of a 100 watt panel is 1005mm x 670mm (39.5″ x 26.5″) which gives an area of 0.673 square meters, or 7.25 sq ft.
What are the dimensions of a 100 watt solar panel?
As my pergola roof is 15m2 (161 sq ft), I’ve no worries there!
I like 100 watt panels because they are easy to handle. I almost always use the flexible solar panels, but more of that later. Of course, there many sizes of panel to choose from – see the size chart below:
Table – Solar panel size and wattage chart
|
Rated Watts |
Length (inches) |
Width (inches) |
Weight |
|
50 |
29.9 |
27 |
6.6 lbs |
|
100 |
39 |
26.4 |
17.6 lbs |
|
160 |
58.3 |
26.4 |
22.9 lbs |
|
200 |
52 |
39 |
32 lbs |
|
300 |
65 |
39 |
40.1 lbs |
|
400 |
81.4 |
41.2 |
56 lbs |
What if you wanted to use all of the roof area to add to your home grid-tie solar power system?
How much power can you generate from your solar pergola roof?
The average garden or home pergola roof size is 12 feet by 12 feet, so 144 square feet.
How many 100 watt solar panels will fit on 144 square feet? Let’s use the dimensions of a a 100 watt panel, which is 39.5 inches long by 26.5 inches wide.
12 feet is 144 inches, so we can comfortable fit 3 panels lengthways – and how many wide?
Divide 144 by 26.5 inches and we get 5.4, so 5 panels.
The total number of 100 watt solar panels we can fit on a 12ft by 12 ft pergola roof is 3 x 5 = 15 panels.
How to calculate solar power generation
The amount if energy any solar panel can generate depends on how much of the sun’s energy falls on its surface. It’s called irradiance.
Although this value varies according to location, professional installers use an average value of 4 kWh/m2/day for estimating purposes.
This value is also known as peak-sun-hours – find yours for your location here.
How much power can a solar pergola produce?
From the previous section we found that 15 x 100 watt panels would fit on a pergola roof size 12ft by 12ft, and that a 100 watt solar panel can generate 400 watt-hours per day at an average peak-sun-hours of 4.
Energy from 1500 watt solar = 1500 x 4 = 6kW per day.
Use the table below to find the amount of solar energy your pergola could produce per day, month and year:
Table – How much solar power from various pergola roof sizes
|
Pergola Dimensions (feet) |
Energy per day (kWh/day) |
Energy per month (kWh/mth) |
Energy per year (kWh/yr) |
|
8 x 8 (64 sq ft) |
3.5 |
106.5 |
1277 |
|
10 x 10 (100) |
4 |
121.6 |
1460 |
|
12 x 12 (144) |
6 |
182.5 |
2190 |
|
13 x 13 (169) |
7 |
213 |
2555 |
|
14 x 14 (196) |
8 |
243.3 |
2920 |
|
15 x 15 (225) |
9 |
273.75 |
3285 |
|
17 x 17 (289) |
12 |
365 |
4380 |
|
18 x 18 (324) |
13.5 |
410.6 |
4927 |
|
20 x 20 (400) |
16.5 |
501 |
6022 |
Are solar panels too heavy to mount on a pergola roof?
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The average weight of a commercially available 100 watt panel is between 17 and 20lbs, and for my pergola that means total weight would be 15 x 20 = 300 lbs.
How much weight can a pergola support?
A good rule of thumb for pergola loading is between 250 and 300lbs, so if I mounted panels on the total roof area I would be pushing that upper limit, if I used rigid panels.
What type of solar panels are best for pergola mounting?
For many applications I use flexible solar panels instead. A 100 watt panels weighs about 5.5lbs instead of 20lbs, so quite a big difference. 15 solar panels at 5.5lbs weight is only 82.5lbs, so there’s a comfortable margin for safety.
Flexible solar panels are much lighter than rigid.
Flexible solar panels have the same area and are just as efficient, but they are much thinner at just a few millimetres. For roof-mounting I build simple aluminium frames to keep them rigid – see image below:
‘Rigidize’ the flexible solar panels with aluminum angles. Solar panels pergola ‘flexible style’ weight 90% less!
What kind of controller do I needed for a solar pergola?
If charging batteries with your solar pergola setup, a charge controller is needed.
For my 300 watt installation I’m using a 30A rated, up to 60 volt input MPPT (Maximum Power Point Tracking) controller.
The open circuit voltage (Voc) of my 100 watt panels is about 21 volts, so I’ll simply connect them up in parallel, taking two wire to the controller input terminals.
MPPT controllers are much more efficient than than standard PWM controllers
I use MPPT controllers in most of my projects for two reasons:
- MPPT controllers are up to 30% more efficient than the cheaper PWM charge controllers
- They produce more power when the solar panels may be partially covered with clouds, for example.
What can a solar pergola be used to power?
Solar panels mounted on a pergola roof can power light, charge batteries and operate water pumps
If used as a stand-alone, off-grid system the solar panels can power typical garden items, such as garden lights, electric lawnmowers, water pumps and swimming pool lights.
A small system like mine (300 watt) would need a 50Ah battery with an appropriate solar charger for devices with no batteries (like water pumps), while most others will just have their batteries charged direct.
If you intend to use the whole pergola roof area to supplement an existing home solar system, this is easily done.
I recommend fitting panels with micro-inverters connected to each panels. Micro-inverters convert DC to AC at the panel level so DC losses are minimized.
AC cabling would then run to the house solar control board and tie in to the AC circuit breaker.
Note: Make sure that existing component capacity can take the extra current from the new solar supply.
My charging system showing panels mounted on solar pergola roof, lithium battery and MPPT control board
How much does a DIY solar pergola cost?
Installing solar panels on pergola doesn’t cost the earth, particularly if you mount and connect them yourself.
This is easily doable and there’s plenty of detailed guides on the internet to help with system sizing. The costs for purchasing the components for my own DIY solar pergola roof were as follows:
- Three 100 watt flexible solar panels – $200
- MPPT solar charge controller (30A rating) – $70
- Cabling and junction boxes – $10
- Aluminum angles and sundries for making solar panel frames – $15
In total, just $305 with no labor, as I mounted and connected everything myself. If this system was to feed any AC appliances, then a 50Ah lithium iron battery would be required at a cost of $250.
Total cost with battery = $555
If I covered the whole roof of my pergola with solar panels to add to an existing grid-tie system, the cost would be:
- Solar panels = 15 x $161 = $2430
- Micro-inverters (5 required) at $150 each) = $750
- Alu. angle iron to make frames for flexible sola panels = $55
- AC isolating breaker and AC cabling to existing solar grid-tie board = $70
Total DIY cost for adding 1500 watts of solar pergola supply to existing grid-tie = $3305 ($2.2/watt)
The average current price for professional installation is about $3/watt, so a DIY solar installation represents quite a saving.
Related post:
How many solar panels do you need to power your home?
Other Questions People Ask:
Can you put solar panels on a patio cover?
Mounting solar panels on a patio cover is a great idea. It may be that your roof isn’t accessible or not suitable, but if you patio cover is well-constructed it’s an ideal place for a solar power system.
If you do have an existing solar system on a roof that is a bit small, you can add extra solar panels to a patio roof cover and upgrade the power output of the whole PV system.
In this case, you can either add another string inverter to cover the DC to AC voltage conversion or install solar panels with microinverters connected to each individual panel.
As with all structures, the patio cover should be strong enough to support several solar panels. A 300 watt panel can weigh about 40lbs. If there is any doubt, you could always use flexible solar panels, a strategy I favor.
What is a solar pergola?
There are two ways to get a solar pergola – either add solar panels to an existing structure or buy one ready-made with solar panels already mounted on the roof (see ‘Where Can I Buy …’ below.)
It represents a great way to set up either a stand-alone off-grid power supply, or add extra solar panels to an existing home solar PV system.
An off-grid type solar pergola could be used for EV charging, or for charging garden appliances, garden lights or water pumps. All it needs is a battery bank for energy storage, and you’re good to go.
Why you shouldn’t put solar panels on your roof?
There are some circumstances when you shouldn’t put solar panels on you pergola roof. If the structure is very flimsy, then it may not support the weight of several fixed-frame solar panels.
A 300 watt solar panel weighs about 40lbs, so several of them are quite heavy. In this case I would resort to 150 watts flexible solar panels, which weight about 5 lbs in general.
The other circumstance which comes to mind is if your roof is shaded by large buildings for much of the day, or by large trees. Trees can be cut of course, but this isn’t very ‘green.’
How do you make a solar pergola?
A DIY solar pergola roof is quite simple to set up, and just requires basic tools and skills.
You will need:
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-
-
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- Suitable sized solar panels (flexibles recommended
- An inverter (if powering AC appliances)
- A solar charge controller (MPPT recommended)
- One or more batteries for energy storage (lithium iron phosphate recommended)
- Cables and junction boxes
- Panel mounting rails
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Key takeaways form building a solar panel pergola
Any pergola or roof of outdoor structures can be used to make a solar patio cover. All that’s needed is enough square footage to mount a solar array to change a standard pergola into a solar pergola as long as the structure can stand the extra weight of solar panels.
Even though mounted on an external structure, the installation can still subject to a tax credit and may indeed be the best option if short of other mounting surfaces. Solar awnings can be used as well, or many other kinds of domestic support structures.
Using an outdoor area for solar is a great way to reduce your electric bill and even small patios can make a significant contribution to powering additional living spaces. Conventional pergolas easily lend themselves to custom designs and can even be closed in to form an outdoor living space.
Some companies market ready-made solutions, such as the Big Kahuna Solar Pergola Kits: a great alternative to a DIY system made from scratch at little additional cost. The Big Kahuna solar ready pergola kit makes it easy.
Solar gazebos and solar carports generally add to the home value and can easily adapted to charging electric vehicles, normally incorporating a battery system for complete peace of mind.
After years of experience I can testify that working with solar electricity is a great experience, either mounting a small amount of panels to feed solar lights or filling the flat roof of a traditional pergola.
Where can I buy a solar pergola?
The Big Kahuna Solar Pergola Kit
The Go Solar Power Pergola
Shade Power – Solar Pergola Installation (San Francisco Area)
Residential Solar Panel Pergolas
Resources relating to Solar Pergola Design:
DIY Grid-Tied Solar Pergola | EnergySage
Solar Pergolas: A Handy Mix of Function and Production
