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It's hard to believe that I've been running my tiny house on solar energy for over seven years now! Living without a power bill for almost a decade has been nothing short of amazing. I wanted to share my firsthand experience with solar power to give you a comprehensive overview of what it takes to run a tiny house on solar energy: the number of panels needed, the costs involved, and much more.
Solar Panels For A Tiny House
Many individuals have approached me about installing solar panels on a tiny house because I'm one of the few fully off-grid homeowners out there. I’ve navigated a variety of challenges, such as how to operate my air conditioning on solar power, how to cook with a solar oven, and how I use solar generators as backup power when necessary.
Tiny houses are ideal for solar energy systems due to their low power needs. While the average American household consumes around 30 kWh per day, my tiny house operates on approximately 3 kWh daily.
Every choice I made during my tiny house construction, from selecting energy-efficient LED lights to installing a highly efficient mini-split system and an on-demand hot water heater, was designed to minimize power usage. Since I built my own house, these decisions were relatively straightforward and didn't significantly impact my budget. The extra costs for high SEER-rated HVAC systems were quickly recouped by requiring a smaller solar panel array and battery system.
How Much Power Does A Tiny House Use?
A tiny house typically consumes around 4 kWh per day. Generally, about 80% of that energy is allocated to heating and cooling, assuming cooking and water heating are done using propane or natural gas.
Here’s a breakdown of my daily power consumption:
- Mini-split (heating/cooling): 3,000 watts per day
- Refrigerator: 780 watts per day
- Lighting: 100 watts per day
- Cell phone charging: 30 watts per day
- Laptop: 240 watts per day
Total: 4,150 watts per day
How Many Panels Do You Need To Power A Tiny House?
Fifteen solar panels are usually enough to power a typical tiny house. This calculation is based on an average-sized solar panel of about 300 watts, which can yield approximately 4,500 watts of solar energy. This system would meet all your electrical needs, including heating and cooling, but would require you to use a gas stove and a propane-heated hot water system. If you live in a colder climate, additional heating with a propane heater might also be necessary.
How Many Solar Panels Can You Fit on a Tiny House Roof?
Typically, you can mount around two solar panels on the roof of a tiny house. This presents a grand challenge, as you can realistically generate about 20 watts per square foot under ideal conditions. This means you might only achieve around 600 watts of production on a tiny house roof, which is quite limited.
Mounting Solar Panels On A Tiny House Roof
While many opt for roof-mounted solar panels, I chose a ground-mounted solar array, and I could not be happier with that decision. Tiny house roofs generally offer about 200 square feet of space, and due to sloping roofs, you can only mount panels on one side. This leaves about 100 square feet for installation.
I secured my solar panels on stands at ground level. After exploring all options—roof mount, pole mount, solar trackers, and ground mount—I find that my decision works flawlessly.
The benefits of a ground-mounted array are numerous: I can easily clean my panels, remove snow buildup after a storm, keep the panels cooler (enhancing their efficiency), and position them in areas that provide cooler shading for my home while remaining in an open field.
The most significant advantage of grounding my array is the ability to install a much larger solar panel system. Instead of having a mere 600 watts on my tiny house roof, I managed to place a 4,000-watt system in the adjacent field.
My Tiny House Solar Panel System:
To establish solar power in your tiny house, you need a few essential components: solar panels, batteries, a charge controller, and an inverter. In simple terms, solar panels capture energy from the sun and convert it into direct current (DC) power. This energy then flows to the charge controller, regulating how power is distributed to the batteries or the inverter, which transforms DC power to alternating current (AC) power that your home utilizes.
Here are the key components of my solar system:
- 3,975 watts (3.9 kW) from Schneider SW — fifteen 265-watt panels
- 1,110 amp/hr battery storage
- 24-volt system
How To Build A Solar Power System For Your Tiny House
Before I proceeded, I had to identify the best location for the solar panels, ensuring they received optimal solar exposure and minimal shading. To assist me, I employed a tool known as a 'solar pathfinder,' a semi-reflective dome that I placed at the location to capture a photo.
Calculating Power Production
When I uploaded the photo into the software and outlined the tree coverage, I also provided my location, date, and time. The software calculates the expected power production based on 30 years of weather data for my precise location and tree coverage. It then provides comprehensive calculations.
This enabled me to set realistic expectations for my solar setup while confirming my assumptions.
Upon verifying that the system would adequately meet my requirements, I built my panel support structure using pressure-treated 4x4s that were each 10 feet long. Each weighed about 300 lbs, ensuring they wouldn’t be affected by windy conditions.
I chose the DIY route because it was more economical than some ready-made options that required cementing into the ground. Since I rent my property, a movable solution was preferable. I believe the total material cost amounted to around $500 for this aspect.
Choosing To Wire For AC Or DC From Solar
Many have claimed on the internet that direct current (DC) is a more efficient way to power devices. Most traditional homes are wired for alternating current (AC), but if you’re installing solar in a tiny house and building from scratch, the choice becomes quite pertinent. Solar panels produce DC power, so it’s crucial to decide how to convert or utilize that.
Most advice advocating for DC wiring comes from older sources that may not have adapted to advancements in technology; these could be outdated articles (anything older than a year may not be relevant) or individuals who have not updated their understanding of solar technology.
In times gone by, the argument for wiring houses for DC power stemmed from two primary concerns: power loss through inefficient inverters (which convert DC to AC) and the theoretical efficiency advantage of DC. However, modern inverters have significantly improved, and although some power is lost in the conversion from AC to DC, this loss is minor. Moreover, any inefficiencies can be counterbalanced by adding an extra one or two panels to your solar array.
As it stands today, wiring for AC may make more practical sense since DC-powered appliances are typically twice or thrice more expensive than their AC counterparts. This means that owners can enjoy higher power output with AC wiring while ultimately saving money with lower appliance costs. In short, converting to AC, adding a few more panels, and then forgetting the AC vs. DC debate often yields the best outcome.
Installing Solar Panels For My Tiny House
After determining the ideal positioning and constructing my stands, I proceeded to install the solar panels. This step was straightforward, and the stands functioned perfectly. I used 250-watt panels from Canadian Solar, wired in groups of three, and subsequently connected them into the system.
Building My Battery And Inverter Cabinet
The next stage was creating a cabinet to house all the equipment. I desired a standalone area because the batteries are quite heavy. Each battery weighs 118 pounds, and coupled with the cabling and additional components, the entire unit exceeds 1,100 lbs. The top and bottom compartments are separated to prevent any gasses from the batteries from drifting into the electrical section, a safety measure that is essential.
On the sides of the cabinet, you can observe the vents. Using lead-acid (LA) batteries can result in some gas emissions during discharge and charging processes. These gases can be volatile and pose a fire hazard, so installing two vents ensured proper airflow.
Choosing Batteries For A Tiny House Solar Panel System
I selected lead-acid batteries due to their longevity and cost-effectiveness. At this time, lithium-ion batteries were not feasible, running around $10,000 for equivalent capacity. My choice of 6-volt batteries stemmed from an economical standpoint, coupled with the reliability of the Trojan brand reputation.
The batteries typically last about 11-14 years, and I anticipate replacing them in about five years as battery technology is expected to evolve significantly by then. New lead-acid batteries are projected to cost approximately $5,000.
Wiring My Batteries For 24 Volts
The batteries are installed in a series-parallel configuration. The 6-volt batteries are arranged in series, creating a 24-volt unit, and I established two such units in parallel. Choosing a 24-volt over a 48-volt system (which is generally more efficient) was largely due to the cost-effectiveness of components and the additional future-proofing it provided.
Future Proofing My Solar Panel System
The 24-volt system allows me to add more panels and batteries effortlessly without necessitating upgrades to the current equipment. This enables the addition of up to 15 panels and various batteries without modernizing the electronics. A significant draw was choosing inverters that can stack, making it simple to integrate another unit should I upgrade to a larger home.
How To Connect Solar To A Tiny House
Once power travels through the system, it emerges from the inverter as AC power. The AC power exits through a thick cable, leading to a 50-amp RV-style plug setup. My reasoning behind using this design rested on two aspects: inspectors generally are less scrutinous of non-hardwired systems, and it enables seamless connections at any RV campground.
The plug connects to a female 50-amp RV receptacle, emphasizing safety by avoiding dual male ends that could create hazardous situations. I ensure the main breaker is off while connecting and then turn it back on afterward.
If these discussions about watts, volts, amps, and watt-hours feel overwhelming, you might want to revisit the basics. I have an eBook titled 'Shockingly Simple Electrical For Tiny Houses' that simplifies these fundamental concepts, covering electrical systems, wiring, power management, and understanding your electricity requirements, although it doesn’t detail solar aspects in depth.
Grounding Your Solar Array
Here's a look at my grounding wire, which is one of two; the other wire is located where the panels are installed. My house also integrates grounding through the cable hookup and the trailer itself. Grounding requirements vary significantly based on many factors, including whether your house's electrical panels are bonded. If this concept is new to you, I recommend conducting thorough research as it is vital.
Using A Backup Generator
Another element of my setup includes a generator, which I relied on for the first two years before upgrading my system because the generator became an inconvenient source of power. During the winter months, topping off batteries was sometimes necessary, especially after prolonged cold and cloudy weather.
I initially had a Honda EBi generator. I appreciated its compact and quiet design, but its limitation of only 120V was a significant drawback. To charge my batteries, 240 Volts were necessary, leading to the acquisition of a 240-volt Generac generator for $650. This generator proved problematic, prompting me to enhance my system and eliminate the need for its use.
Tiny House Solar Panel System Costs
The critical factor when considering solar power is undoubtedly the cost. Most individuals desire solar energy, yet prices act as a major constraint. My transition was straightforward once the power company quoted approximately $15,000 to extend their power line to my home, along with monthly bills.
The initial investment for my solar panel array and batteries amounted to around $14,000, yielding the advantage of zero power bills and a $7,500 tax credit. Consequently, the decision became quite straightforward. I later expanded my system for an additional $5,000 while enjoying a further $2,500 tax credit.
In essence, I effectively saved money from the very beginning, although I had to front that substantial cash payment, which isn’t feasible for many individuals.
Here’s a rough outline of costs for my upgraded solar panel system:
- Inverter: $4,500
- Charge Controllers: $1,200
- Control Panel: $300
- Batteries: $4,000
- Solar Panels: $4,000
- Breakers + Boxes: $800
- Battery Cabling: $300
- PV Wire + House Tether + Romex: $500
- Electrician (labor): $2,000
Is Solar Practical For Tiny Houses?
Generally speaking, I find that solar energy is a practical solution for stationary tiny houses. Even if solar is not your immediate choice, the cost advantages of tiny living can facilitate saving for an eventual installation. While renting an apartment, my bills averaged $150 per month—compared to about $15 for my tiny house (no typo!). Living in a tiny house has allowed me significant savings while enjoying comfortable living.
This summary highlights the crucial components of my system, and I plan to create future content that addresses sizing, component selection, installation, and additional details for implementing solar energy for your tiny house.
Your Turn!
- Are you considering solar power for your tiny house?
By
Ryan Mitchell
on April 10,
/
Tiny House
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