So you want to take the ultimate plunge in tiny house living: creating your own electricity. Whether you’re a first-timer or veteran electrician, there’s nothing more exciting than turning on a lightbulb and knowing that your own solar panel system created the energy to power it, with nothing but good ol’ sunlight.
But figuring out everything there is to know about electricity can be confusing, and if you don’t have the proper training, it can feel like an impossible task.
So how do you wire a tiny house for solar power? It begins with understanding the basic components that make up a solar panel system – generally a set of solar panels, a charge controller, a battery bank, and an inverter – understanding how the flow moves from one end to the other, and finally connecting these pieces with the appropriate positive and negative wires in the right places.
By the end of this article, you should have a foundational understanding of tiny house electricity demands, the cost and set up of a solar system, and installing solar panels and how to wire your tiny house’s own PV system.
How Do Tiny Houses Get Electricity?
You've seen tiny houses parked in the middle of nowhere on Tiny House Nation and wondered, "Wait a minute, how do they power up any appliances?"
A tiny house sources electricity in two ways: by staying on the grid or by creating its own version of a solar farm.
A grid-tied system means complete dependency on the city's electricity line. Its electric configurations are similar to what you'd find in a normal home. It's easy to set up and you don't have to worry about building your own system to power up your home.
On the downside, being grid tied can mean power outages will affect your electricity like any other home. This also means you can't bring your tiny house out for an adventure because you're completely dependent on the grid.
A tiny house running on solar power gives you the ability to tow your tiny house just about anywhere. When you have your own solar system, you can set up in completely rural areas and still power up city comforts like a water heater and even a refrigerator.
How Much Does It Cost to Set Up a Solar System?
Setting up a solar system can be pretty pricey upfront, but the good news is that the costs have been going down every year thanks to constant innovations and continuous demands for accessible solar systems.
Just a decade ago, the cost of setting up a 6kW system cost upwards of $50,000. In 2019, the same system can be set up for $16,000.
Determining the cost of your solar power system depends on a variety of factors including where you live and how much energy you need.
You can use these factors to get an idea of how much you need to shell out for a functional solar power system for your tiny house.
Solar Panel Costs by State
Energysage suggests that the average cost of solar panels are affected by the average electricity cost of each state.
In Florida where the cost of electricity per watt is cheaper than the national average, installing a 6kW solar system can cost you $9,000. Compare that to New Mexico, where electricity cost is higher than the national average, the same set-up can cost you a minimum of $12,000.
Solar panel costs are charged per watt. The average cost is currently $2.98, which means that if you need 2 - 3kW to power up your home, you’re going to spend anywhere from $6,000 to $9,000 to set up a small-scale system.
A standard 6kW system can power a bunch of powerful appliances, but if you’re only looking to run some lights and chargers for your laptop and flashlight, you can definitely get away with a much smaller system that costs a lot cheaper.
Wholesale Solar shows the difference in costs based on your energy requirements, from something as manageable as 3kW to something more heavy-duty like 8kW.
Are You Grid-Tied Or Completely Off-Grid?
Based on the previous table, you’ll notice that the cost of a grid-tied system is cheaper than an off-grid system. This is because powering your tiny house 100% on solar panels requires additional costs that would enable you to live independently, without being hitched to any electrical supply.
This involves buying reliable batteries that can store as much power as you need for longer periods of time. This also involves setting up enough solar panels to provide everything your house needs in terms of power.
Solar Panel Efficiency
As we mentioned earlier, the cost of a solar panel is based on its wattage, not its size. Standard solar panels come in the 60-cell or 72-cell configuration, fit for residential and commercial use respectively. When we say “cell”, we’re talking about the individual blocks that come together and make up one panel.
A standard 60-cell panel measures (LWH) 65 in x 39 in x 1.5-2 in. Even if you buy the same size panel from two different companies, the cost can end up different because of its energy efficiency.
Solar panels have only been increasing in efficiency with their technology over the last few years, with the latest solar panels now averaging up to 18-21% efficiency, as opposed to 12-15% a decade ago. With greater efficiency comes greater energy production, meaning more appliances can be powered with the same area space of solar cells.
A panel can have varying outputs ranging from 150W to 350W. The lower your wattage, the cheaper the solar panel is. However, you might need to buy more of it in order to meet your energy demands. Further below, we discuss the number of solar panels the average tiny house needs to generate sufficient power.
How to Calculate Your Tiny House's Solar Power Requirements
Ultimately it all boils down to your power consumption. Not every tiny home is going to be consuming the same amount of energy. A tiny house with a propane stove and heater running a few lights and a ceiling fan will have lower energy requirements than a home that has power-hungry appliances like an electric stove and refrigerator.
An online solar power calculator can help you convert your current electricity load into a solar power system, giving you a rough idea of how many solar panels you need based on the capacity or wattage of one solar panel your required kWH for the month.
How Many Solar Panels Does It Take to Power a Tiny House?
The number of solar panels your tiny house needs depends on your energy consumption. The average sized home and family in the United States consumes roughly 10,000 to 12,000 kWh per year.
For a tiny house -- where there are fewer energy needs and the house is partly powered by propane and other power sources -- some owners report a low average of 914 kWh per year, while others report an average of 100 - 120 kWh per month.
The number of solar panels your tiny house needs will depend on three factors:
- Hours of direct sunlight per day
- Your tiny house average daily energy consumption
- The wattage of your solar powers
The averages for those three factors are 5 hours of direct sunlight per day, 100 kWh of energy per month, and 290 watts per standard-sized solar panel. Using the average numbers above, the average solar power produces 290 watts per hour, multiplied by 5 hours of direct sunlight. This results in just below 1.5 kWh, or 45 kWh per month.
|Solar Panels||kWh per Month|
|1 Standard Solar Panel||45 kWh|
|2 Standard Solar Panels||90 kWh|
|3 Standard Solar Panels||135 kWh|
|4 Standard Solar Panels||180 kWh|
The average tiny house then needs roughly 2-3 standard 290-watt solar panels, producing roughly 90-135 kWh per month, or 1080-1620 kWh per annum.
Wiring Your Tiny House to Solar Power
Step 1: Know Your Energy Requirements
Before anything else, it’s important that you know your daily and monthly energy requirements. If you have been hooked to the grid and have old utility bills, then this should be easy to figure out.
Just find the “Used kWH” label on your bills, and check if it is noted as per month (it should be if your bills come in every month like most do). For bills that do not indicate the kWH, simply check the meter readings. With the meter readings, subtract the last one from your most recent reading, and that should be the right number.
Remember that you need to find the daily average of your kWh rather than a monthly or yearly total, so divide as needed by the number of days in a month or a year.
If you do not have previous utility bills, then you will need to go over your tiny house’s appliances one by one. Add up all the appliances that will be using electricity, adding up their energy needs. Remember not to include appliances that you will be powering in other ways, such as propane-powered devices.
You can also do the easier option of inputting your details into the solar off-grid calculator mentioned above and trusting their results.
Step 2: Figure Out Where Your Solar Panels Will Go
While the easy answer is to put your solar panels on your roof, this isn’t always an available option. If there is something stopping you from mounting your panels on the roof, then you can opt for a pole-mounted or ground-mounted system.
Make sure to find a spot where your panels can have direct contact with sunlight, with no shadows in the way. You can use a solar path finder tool that can help you figure out the best placement for your solar panels surrounding your home, with specially designed software that calculates for optimal sunshine.
We highly recommend keeping your solar panels on the ground instead of the roof, for a number of reasons:
- Roofs can get pretty hot during the warmer months, and as counterintuitive as it may seem, solar panels actually lose efficiency when they become overheated
- Solar panels on the ground are more accessible, thus easier to monitor, fix, and clean
- You might prefer to keep your tiny house in the shade rather than in the face of direct sunlight, allowing it to stay cool
- It can be difficult to reposition your solar panels if they’re on the roof, as you will have to reposition the entire house
Step 3: Build Your Racking
With solar panels on the ground, you will need to build a racking system to keep them angled towards the sunlight. This isn’t as complicated as it seems – simply build a frame that your panels can rest on at an angle facing the sun, bolted in place. Your racking can look like a homemade, wooden version of this:
As you will probably prefer a mobile option for your racking system, you can use simple wooden boards for your racking, allowing you to assemble and disassemble your racking for when you move.
Materials for a 10’-long rack can cost you anywhere from a few hundred dollars to a thousand dollars, depending on the type of framing you buy. The heavier your racking system, the safer your solar panels will be, as heavy racks can keep your panels grounded even through the toughest weather.
Step 4: Install Your Solar Panels, Wire Your System Together
Now you will need to mount your solar panels to your racking and start with the wiring. This is where it gets tricky, and if you’re a newbie with electrical systems, you’ll need a basic understanding of two different sides: the individual components of an off-grid solar power system, and the basics of solar wiring.
|Solar Panels||The panels that convert sunlight into energy, transforming it into electricity. The average solar panel generates 250 – 300 watts per hour.|
|Charge Controller||The solar panel channels the energy through the charge controller, which sits between the panels and the batteries. The charge controller ensures that a steady flow of energy is transferred into the batteries, preventing the risk of overcharge.|
|Battery Bank||The bank of batteries that store the solar panel-generated electricity. The more batteries in your battery bank, the more electricity you can store.|
|Inverter||The electricity generated by solar panel is DC or direct current, and most appliances that we use need AC or alternating current. The inverter converts the DC electricity into AC.|
|Battery Monitor||This is your window into your battery bank, giving you a look into the numbers detailing the energy going into your batteries from your panels, and out of your batteries into your appliances.|
How to Wire Your Tiny House Solar Power System Together
Now that you understand the basic components that make up a typical solar power system for a tiny house, let’s go over the exact wiring scheme you will need to follow to make everything work.
When all your solar power system wiring is done, your wiring scheme should look something like this:
Need something simpler? This diagram breaks it down more easily:
Remember that the purpose of your wiring is to transfer electricity from Point A to Point B, so your wiring should always follow a logical system with a beginning (the solar panel) and an end (electricity for your appliances). The components involved in transforming sunlight into usable electricity are those listed above, or the solar panels, the charge controller, the battery bank, and the inverter.
Here’s how they fit together:
- Wiring: What kind of wire should you use? While most full solar panel systems will have their own wires included in the kit, if you need to purchase your own wire, you can’t go wrong with copper stranded wire.
- Solar Panels: Solar panels convert sunlight into DC power, and out of each panel there should be two wires: a positive and a negative. If you have multiple solar panels, you will have several positives and negatives, and these need to be consolidated into a single wire with a combiner box. A combiner box allows you to plug in multiple solar panel wires, resulting in an output of a single positive and negative wire.
- Charge Controller: The single negative and positive wire from your combiner box should now be plugged into the input of your charge controller. Now on the output end of your charge controller, another set of positive and negative wires need to be connected to the device.
- Battery Bank: The set of positive and negative wires coming from your charge controller’s output end should now be linked to your battery bank, with the positive wire connecting to the positive battery bank end, and the negative wire connecting to the negative battery bank end. If everything has been set up properly so far, congratulations: you are now converting sunlight into stored energy. The problem? All the energy is in DC and needs to be converted. (The battery monitor should also be connected to your battery bank.)
- Inverter: With another set of positive and negative wires connected to their respective ends on the battery bank, link their opposite ends to your inverter. The inverter will transform the energy from 12V direct current (DC) power to 120V alternating current (AC) power. When your energy is converted into AC, it should now be usable for most standard devices and appliances.
- (Optional) Grounding: The decision of whether to ground your solar panels is one that tiny house on wheels and RV solar panel enthusiasts often debate – while some claim that there is no purpose or need to ground a typical 12 volt battery panel, others want to take extra precaution to be safe. If you decide you want to ground your system, you will need ground wires connected from your solar panels, your charge controller, and your inverter, with all three grounded to the chassis of your tiny house trailer.
Tiny House Solar Power System: DIY or Hire a Professional?
With all that said, you might be ready to answer the question: are you going to install your solar panel system yourself, or will you hire a professional electrician for help?
If it’s your first time dealing with electricity and if you’re not confident in your abilities to understand every instruction to the letter, then you might not want to be handling thousands or tens of thousands of dollars’ worth of equipment and potentially messing up.
However, we understand that most people get into tiny house living because they want to live independently and do everything themselves.
If that’s the case, then there are plenty of consumer-friendly off-grid solar power system kits available on the market, with helpful manufacturer customer support should you run into any trouble.
And if you hit a wall that you can’t get around, then the option to call in a professional electrician is always on the table.
Our biggest bit of advice? Setting up your own tiny house solar panels can be pretty intimidating, especially if you don’t have much experience with electronics and appliances. But as long as you take in and understand each part of the system one at a time, you should be converting sunlight into usable electricity in no time. Good luck!
Hey, there! We're Ivan and Manuela from Croatia, and we're crazy about tiny houses. We don't own one (yet).
This website is a result of our passion to share all the knowledge, photos, tips and tricks that we were able to learn while studying everything possible about the tiny house movement.