Designing our skoolie solar system for off-grid living had to be one of the most challenging components of our build.
We spent so many days and nights studying, researching, and learning all things solar. David and I’s goal with our build was to be able to take the bus into snowy locations for long periods of time. We wanted to spend our winters north to chase pow storms and snowboard. As a result, building a high-quality solar system was absolutely imperative to our comfort while living on the bus.
Of course, everyone’s energy needs are going to be completely different. We put an overemphasis on winter months, whereas you may only plan on chasing the warmth throughout the country, which usually means more sun!
Regardless, I’m going to break down our solar system setup including most of the parts, materials, and resources that we used to make this happen. While everything can’t always be perfect, we hope that our setup can help you build your dream system!
We’ll also be releasing a few more articles about all things solar, including an in-depth guide into calculating your solar energy requirements. Be sure to sign up for our newsletter and follow us for frequent updates!
Please note: We are by no means professionals. I would highly recommend that you do your own research to get a better understanding of solar before jumping into your own electrical setup.
Quick Summary: What’s Required for a Skoolie Solar System
While there are a variety of different ways that you can build your system, there are a few basics that you should understand to start with. In order to make our shopping list a bit more understandable, the following are some of the components of a successful solar system.
- Solar Panels: Captures solar from the sun and converts it into usable energy.
- Charge Controller: Takes the current from solar panels and charges your battery. Controllers also help with limiting and controlling that power.
- Batteries: Stores the DC electrical energy for use at another time.
- Inverter: Converts DC into AC power.
Once your solar energy is funneled through this basic process, you’ll be able to turn on a light and charge your phone! Sounds simple enough, right?
How Do We Charge Our System?
Our setup, like many others, can power 12V DC (lights, water pump, fan) and 120V AC loads (Laptop, freezer to fridge conversion, UV sterilizer). If you’re looking for a really detailed wiring diagram, check out Far Out Ride. It really goes in-depth into the components regarded for making a typical electrical system.
- Solar panels – As mentioned above, we get most of our power from the sun! On good days, we can run our air conditioner nearly all day.
- Shore power – This allows us to hook up to charge our batteries at an RV park, campground, or someone’s house. It takes 120V and goes through a regular wall outlet to drop the volts down to 24V. In turn, our battery charges!
Another common way to charge your battery is through the bus’ engine while turned on. Alternators on buses are a great way to get an extra charge on your batteries while on the road. If you choose to go this route, you will need an isolator. They help with charging the house bus batteries without draining the bus batteries.
Calculating Our Energy Budget
Taking the time to calculate a realistic energy budget could make or break your solar system on your skoolie. If you don’t add enough power, you’re going to max out and drain your battery way too often. On the other hand, adding too much solar could cost you your entire budget! So, how do you really get an understanding of what’s realistic?
To calculate our energy budget, we first started by creating a spreadsheet to separate our DC and AC electronics.
We then highlighted everything (and I mean everything) we needed to factor into our solar usage. Included were also those electronic’s draw in watts, draw in amps, hours used, amp-hour use, and watt-hour use. Below is a brief idea of how we organized our list. We will go a lot more into what all of this means in future articles where we break down everything solar for off-grid living.
Our Skoolie Solar System Setup
We currently have (4) 355-watt solar panels that total 1420-watts of solar. We chose a 233 amp-hour lithium-ion Tesla battery at 24V. Our lithium-ion battery to lower than 75% its capacity to maximize its longevity and efficiency.
We’ve lived on our bus for nearly a year now and can’t complain about our solar setup at all. When we’re fully charged, we’re capable of running our AC, power tools, fridge, and TV without any issues nearly all day. We run into some more challenges during the winter. We planned our battery and solar setup in the anticipation that we wouldn’t have sun for at least 3 days. There have been several times that we’ve had to hook up to a generator to charge our battery up when we’re experiencing snow.
During sunny days and spring/summer months, we have absolutely no problems. We have enough energy to fuel our needs and then some. One thing we definitely have not had to stress on during our boondocking experiences is solar energy.
We got our panels off of a solar liquidating site. You can most likely find something if you search “solar wholesaler” in your state. Some other great options for finding cheaper panels are through Craigslist. Ours are standard household panels.
We went with 2 MPPT charge controllers for a few reasons. For one, lithium batteries require specific charge controllers. In addition, our left side of panels tilt upwards, so the side that doesn’t get as much sun will be the determining factor in how much the string puts out. MPPT controllers take the higher voltage from our house panels (37v) and brings it down to the exact voltage you need. In our case, that voltage is 24.
Giandel 2000w Pure Sine Wave Inverter
We opted for a DIY battery lithium system. When you’re building a DIY battery system, you’ll need special circuits to monitor the voltage, temperature, and ensure it’s not being discharged too much.
We found our Tesla battery module on eBay. You need to make sure you can interface with the battery balancing/sensing wires. Make sure you either get option 1/2 from below, or you have a battery module with wires NOT a ribbon cable for balancing. The ribbon cables are VERY brittle and you will break them if you are not careful.
Want to see our battery schematic? Click the following link:
Tesla Model S Battery Module Panasonic 18650 3200mAh Cell
Tesla Model S/X OEM Lithium Battery Module 22.8V 5.2kWh 18650 444 Panasonic Cell
Other items we used to build our battery system include: