Solar systems are at the core of any self-respecting off-grid system and we get more questions about the mystical world of solar power than any other single off grid component. There are so many options that it can be overwhelming to know what is best for you and your needs. And let’s face it, most of us are not DC power experts or solar gurus, so you are left with that hopeless “I don’t even know where to start” feeling. Well, you’re in luck because we just so happen to work with some excellent solar technicians and we’ve picked up a thing or two that we will now share with you.
Unfortunately it’s a little more complicated than "I want to be off grid and just run on solar." Most people have a fairly romantic notion of what this entails and don’t think about the practical considerations or lifestyle alterations that they will need to make. A truly off-grid system means you are your own power company. A basic off-grid system has the following components: solar panels, an inverter, a charger controller and a battery. The size of the solar system (number of panels, number of batteries, size of charge controller and inverter) directly determines the amount of power that your system will produce. So, in simple terms, your system needs to be big enough to make the amount of power you will use. The larger the system the more expensive it is. Nothing personal. Just the way it is.
There are relatively straightforward calculations that are done that determine how many amps per hour/day/week that you will use. This is based on how many appliances you use, how efficient those appliances are, and how much time per day you use them. To design a solar system we get this information from you and calculate the size of the system you need based on that. If you are one of those people that NEEDS to blow-dry your hair every morning, while doing a load of laundry, watching TV, toasting some delicious toast AND blasting your A/C on high, this can be done off-grid, but you are gonna need a ginormous solar system and a backup generator for when you inevitably deplete the batteries. Panels and batteries for a system like this won’t fit completely on your roof or in your tiny house and you would need an accessory building to house the batteries and the panels would need to be on an array. This type of system could cost in the $30k-$35k range, depending on your exact needs.
“But Jeremy, I want to spend $15k or less on my solar system." You can definitely do this, BUT you will have to change your power consumption habits. The largest off-grid solar system that would fit on a tiny house (panels on the roof and batteries stored in the house) would cost in the $13k-$15k range. This size of system would allow you to run all your lights (provided they are LED), charge phones, computers, and run small low-draw appliances (fans, clocks, radio, small to medium LED-TV, and small efficient fridge). It would give you up to 3 days of autonomy, this means that if you don’t have much sun for 3 days your batteries could store power to last that long (depending on how much power you use). You would also want a generator to back up the solar panels and to run any large appliances on.
The smallest off grid system you would want in your house would cost in the $5k-$6k range and this would only allow you to run LED lights, charging phones and computers, and very small appliances for up to 1 day of autonomy (mileage will vary).
There is another option, though, that most people don’t know about, that we think is the BEST type of solar system to have in a tiny house. It’s called a Hybrid or Bi-Modal system and next week’s blog will be all about them.