How to Build Your Own Solar Power Generator for $250

Are you kidding me?

No, we’re not. We will really show you in general terms how you can setup your own off-grid solar power system for $250. Building your own solar power generator is very satisfying, but before we get started, please note that installing solar panels does carry some inherent risks and is not something you should be doing if you have NO experience in electrical wiring. You can get a nasty electric shock while doing high-voltage wiring, but the risk doesn’t end there. If the components are not wired properly, a power surge can damage the inverter and possibly cause a fire. Improperly cut wires can be shorted out by rain and also cause a fire. Also note that some states require you to have certain certifications to legally wire solar panels. You should also be aware that all equipment and installation must comply with all local, state, and national building and safety standards.

solar power generator
NASA’s fancy solar power generator: bet you can make one cheaper! (photo credit: NASA)

What do I need to build my own solar power generator?

As we discussed in a previous article on off-grid systems, in order to build your own solar power generator, you will need at the minimum a solar panel, a charge controller, at least one deep cycle battery, a battery monitor, mounting, and wiring. If you are connecting it to your cabin to power your AC devices, you will also need an inverter. If you’re just using it for powering DC devices such as your camera, flash light, RV, or boat electronics, you can do without an inverter.

Let’s take a closer look at these components and go over some examples.

The solar panel: Converting sunlight into DC electricity

The solar panel is at the heart of your solar power generator. It’s also the most expensive component you will need (although the prices of solar panels have been decreasing steadily over the last few years). In order to connect your solar panel to a battery you will need a charge controller. You will also need mounts to secure your panel on your cabin, boat or RV. One recommended option is to purchase an off-grid starter kit. For example, the Renogy Solar off-grid solar kit includes a 100-watt polycrystalline solar panel, a 30 Amp PWM charge controller, a pair of 20 feet MC4 connector adaptor kit (wires) with male and female connectors, and Z brackets (for mounting the panel). However, this kit does not include some of the other components we need, such as the battery, battery monitor, or an inverter (optional). If you’re wondering how much power you can generate using a 100-watt solar panel at your location, check out the handy solar panel calculator we built for you.

The battery: Need to keep those electrons bottled up for later use

A battery is one of the key components of your solar power generator. While you may be tempted to salvage your old car battery and repurpose it for your solar project, this is not a good idea at all. For both safety and performance reasons, you need a “deep cycle” battery as opposed to a regular car battery. Picking a Sealed Lead-Acid (SLA) model is also a good idea, so that you don’t have to deal with filling up the battery with distilled water. This makes the batteries relatively, maintenance free.  This type of batteries used to be quite pricey, but there are plenty of cheap (but OK quality) alternatives in the market today. For example, check out the 12 volt 18 amp-hour deep-cycle lead acid battery by Rhino. You can start with a single battery and expand your system over time by adding new ones and hook them together in series.

The battery monitor: Keeping an eye on the remaining charge

Some people say a battery monitor is optional but in our view, it’s highly recommended. Without a battery monitor, you will have no idea how much charge is left in the battery. Make sure you purchase one that shows you amp-hours such as the MinnKota Digital Battery Meter. An amp-hour meter is a better choice than a standard multimeter that only provides information on the voltage and amperes at any given moment. After all, we wouldn’t want you to run out of power just when you need to charge your mobile electronic devices, would we?

What about those AC devices you need to power? We need an inverter for that

So far, your total cost is around $200 before taxes and shipping. If you are not going to use your system to power any AC devices (such as standard electrical appliances and lights), you are done! However, if you need AC power, you’ll have to buy an inverter to convert DC power generated by solar panels into AC power. You need to connect the inverter to your battery. A Bestek 12v to 110v inverter can do the job by providing 600-watts of continuous power with 1600 watts of surge power capability.

Now your shopping list is complete: Time to order and get ready for installation

Even with an inverter, your total cost now is around $250. Taxes and shipping may put you over our budget, so it’s always a good idea to find components that may ship free. You’re done with shopping! The next step is hooking everything up which is beyond the scope of this article. There are plenty of resources online such as the website Build It Solar. Nonetheless, if you don’t have prior experience with electrical systems, we recommend that you go to your local hackerspace or DIY workshop where you can get some expert help and share the excitement of DIY solar panels!

We’re go for solar

As you can see, finding the components for portable solar panels isn’t too difficult. However, it’s important to note that your initial research and planning is critical for success. It’s also the best way to avoid headaches and anxiety when the fun begins with the installation. The products we outlined above are just some examples. Depending on your power requirement and the available budget, you may wish to buy a different type of solar panel and add more batteries. Estimating the amount of energy you can generate at your site is easy: just go to Sunmetrix Discover, enter your location and get your estimates with a few clicks.

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