How to Build a DIY Solar Generator: In-detail Instructions

Last updated: Nov 09, 2020

Solar power generators are both cool and useful. With a DIY solar generator, you can power some of your home appliances throughout the day to cut down on your electricity bill. Or, you can build a DIY solar generator for camping, for running power tools out in your yard, or for just about anything else you might use a traditional gasoline generator for. Best of all, a solar generator can help keep your essential appliances running indefinitely (at least, during daylight hours) in case the power grid goes down for an extended period.

Building your own solar generator is much less expensive than buying a premade one, and it’s surprisingly simple even if you’re not much of a DIYer. In this guide, we’ll walk you through everything you need to know about how to build a DIY solar generator so you can start using the sun as your energy source.

Why build your own DIY solar generator?

How to Build a DIY Solar Generator: In-detail Instructions

The number one reason to go the DIY route when it comes to solar generators is cost. Name-brand solar generators cost upwards of $2,000, which eliminates nearly all of the cost savings you would get from using the sun for energy rather than gasoline or the electric grid. By comparison, you can build a custom DIY solar generator for less than $500.

Another reason to build your own power unit rather than opt for a packaged model is that you can customize it to meet your needs. Want a built-in light, high current ports, USB outlets, or another custom feature? You can add that into your DIY solar generator.

Building your own solar generator also means that you know what all the parts are and what they do. This is important since it allows you to maintain your generator over time and replace parts as they go bad. Whereas you might have to scrap a $2,000 premade solar generator when the panels start to fade, for example, you can simply replace that part on your DIY unit and keep on producing power.

Of course, there’s one more big reason to go the DIY route – it’s fun! Whether you’re a seasoned DIYer or a novice to electrical diagrams and wiring, building a DIY solar generator is a relatively straightforward and highly rewarding project.

What will I need to build a solar generator?

Picking out the parts that you’ll use to build your solar generator is one of the most exciting parts of this project. There’s a lot of leeway to customize components to fit your vision, so feel free to look for alternatives to the components we’ll suggest.

The first thing you need is a case to build your solar generator in. This is essential to making your solar generator portable, allowing you to protect it from bad weather by moving it inside, take it camping, or to move it around your home to follow the direct sunlight. You could use a large plastic container from your local box store, which would be extremely cheap – and many models are mounted on wheels. If you’re worried about protecting the internal components, consider something a bit more heavy-duty like a Pelican case or a sturdy suitcase.

Next, you need a power inverter. Solar panels produce DC power, but most of the appliances and electronics in your home run on AC power. The wattage of your power inverter is important, since you want to have enough wattage to use all of the power that your solar panels can produce. Unless you’re using multiple panels, a 2,000- or 3,000-watt inverter should work well.

Of course, you’ll also need to pick out your solar panel. There are a ton of options and different panel materials, each with their own advantages and disadvantages. For a 2,000- to 3,000-watt inverter, you’ll want to look for a panel that produces about 100 watts. If possible, look for a kit that includes not just a solar panel, but also a solar battery charger and wiring cables.

The last major component you need is a battery. Ideally, look for a deep cycle battery that can be discharged repeatedly without reducing its lifespan. Importantly, your battery should also be able to be used in any orientation, since your portable solar generator may be used when it’s laid down or stood upright.

In addition, there is a variety of smaller components that you’ll need to build your DIY solar generator:

  • 20-amp GFCI outlet panel
  • AC battery tender
  • Battery cables
  • Fuse block
  • Negative bus bar
  • 14-gauge wire
  • 16-gauge speaker wire
  • Wire connector kit
  • Fuse kit
  • Silicone sealant
  • Screws and fasteners (multiple sizes needed)

These components just cover the basics for building your own solar generator. You can also customize your design and add LED lights, additional outlets, and a voltmeter. Adding these is relatively straightforward – just make sure you buy a large enough fuse block and extra electrical wire.

Step-by-step instructions

How to Build a DIY Solar Generator: In-detail Instructions

Now that you’ve assembled your components, let’s walk through how to build a DIY solar generator.

  1. The first step in building your DIY solar generator is to figure out where the GFCI outlet panel, which is what appliances will plug into, will go. Where exactly you want to place these depends on the case you chose to build your generator in, but it should face outwards so you can draw power without opening your case. It’s a good idea to orient the case the way it will sit most of the time when the generator is in use to determine where the outlet will be easiest to access.
  2. Use an X-Acto knife or drill to cut a hole into your case that is just large enough to fit outlet panel – you don’t want to leave extra space, or it will be more difficult to waterproof your generator. After it’s mounted in place, use the silicone sealant to lock it in and seal out moisture.
  3. Now, open up the case to figure out where you’ll mount the power inverter and battery. The battery is the heaviest component, so it should ideally sit on the bottom of the case, near the wheels. The power inverter should be situated so that the outlets are near the GFCI panel and the 12-volt power cables are close to the battery terminals. Once you’ve decided on placements for these parts, go ahead and drill them into the case with screws and fasteners.
  4. Finally, you’ll need to mount the AC battery tender, solar charger, fuse block, and negative bus bar. These can go wherever you have space remaining inside your case. Ideally, they should all be easy to access since you’ll need to wire them after installation. Once again, use screws and fasteners to keep them fixed to the case.

Okay, now that you’ve got all the components mounted, the next part of our DIY solar generator instructions is all about wiring.

  1. To start, connect the cables from your power inverter to the battery. The red cable should go to the positive terminal, and the black cable to the negative terminal. When you’re done, plug the GFCI cord into the outlet on your power inverter.
  2. Next, it’s important to ground the battery and connect it to the AC battery tender and solar charge controller. Run one battery cable from the negative battery terminal to the bus bar, and another from the positive terminal to the fuse block. Place a 30-amp fuse for the solar charge controller on the fuse block and a 5-amp fuse for the battery tender. Then, use your 14-gauge wire to connect these components to the fuses you just put in.
  3. At this point, all that remains to be done is to connect your solar panels. Connect the speaker wire to the solar panel by crimping together the red speaker wire to the positive panel outlet and the black speaker wire to the negative panel outlet. It’s a good idea to wrap this connection in electrical tape to provide some basic waterproofing.
  4. Unspool the amount of wire you want for your panel. There’s a bit of a balancing act here – you want to have enough wire to place your panel where you want it, but not so much that there’s a big voltage drop from the panel to the charge controller. Once you have the right amount of wire, strip the ends of the wire and connect it directly to your solar charge controller.

That’s it! At this point, you should be able to activate the charge controller on and start collecting sunlight to charge your battery.

Safety tips

Whenever you’re dealing with electricity, safety is paramount. The main thing to keep in mind when wiring your DIY solar generator is that even if you’re not collecting energy, the battery is live throughout the process – treat it as such. It’s important not to allow wires to inadvertently touch each other once they’ve been connected to the battery.

One thing to keep in mind is that most solar inverters are designed to be connected to the grid to operate. When the grid goes down, your inverter won’t operate. This is an important safety feature – if you continued to supply power to your home when the grid is down, you could backfeed the power lines and endanger utility workers trying to fix them. If you want to run your solar generator when the power grid goes down, you’ll need to hook your generator up to a transfer switch just as you would for a gasoline-powered generator.

FAQ

How large a solar generator system needs to be depends on what you’re trying to power. The system we described is designed to handle up to around 2,000 watts – that’s enough to power your lights, refrigerator and freezer, and a few other small appliances. If you want to power your whole house via your solar generator, you’ll need a system that delivers 5,000 watts at the very least. In this case, you will need a larger inverter, additional outlet panels, and more solar panels.

Yes, your solar generator can deliver power anytime the sun is shining – regardless of the temperature outside. That said, the days are shorter and light less available, so you will likely see a drop in power delivery. If it gets very cold, you might also lose efficiency in your battery. The good news is that the delivery of your solar panels actually increases as it gets colder outside.

You don’t need any permits to build your own solar generator. The only situation in which you would need a permit is if you wanted to permanently mount the solar panel on your home. But, in that case, your generator would no longer be portable and you’d have to be very careful about weatherproofing your design.

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