How to Build Your Own DIY Solar Generator?

As of 2017, solar energy is the cheapest source of energy in the world and one of the rare few alternative sources that cause no pollution or negative environmental effects.

Solar energy users worldwide save the planet 75 million barrels of crude oil each year, which is a huge step in making our planet green again.

But apart from being eco-friendly and cheap, solar energy is also incredibly convenient — you can access it everywhere and use it any time, even at night.

A DIY solar generator is a self-contained and portable mini-power plant that you can use to power and charge your gadgets and even small appliances and be 100% independent from the grid.

Read on and learn how to make one yourself.

Parts and Components

First, you need to find all the necessary parts and components that go into your solar generator.

Battery — Your generator needs a battery to store solar energy. Batteries come in all shapes and sizes, but your best shot is either a lithium-ion or deep-cycle lead-acid battery. Here are the advantages of both types:

1.   Lithium-ion (Renogy 12V 170AH Lithium-Iron Phosphate Battery)

2.   Deep cycle lead-acid (Renogy 12V Deep Cycle AGM Battery)

Here's a helpful video that talks you through every single one of these parts and components.

Tools

To build your solar generator you’ll need a few basic tools that include:

1. Automatic wire stripper with cutter
2. A set of Phillips, flat and Torx screwdrivers
3. 111-240V hot glue gun
4. Cordless drill with drill bits and grinding extensions
5. Utility knife
6. Files

Steps

Step 1. Calculate Your Energy Needs

If you need the generator to power your devices and the occasional appliance [2] on your boat or RV, or during a power outage in your home, check out this list of typical power ratings for some of the most common devices:

Step 2. Test the Equipment

First, you need to test the panel and the charge controller.

1. Plug the two pigtails cords coming from the panel in the appropriate (+) and (-) sockets on the charge controller.
2. Now, hook the controller to the battery.
3. When you hook the negative cable, a green light on the controller should light up — showing that the battery is charged.
4. Flip your panel towards the window to make sure it’s picking up sunlight, and another green light on the charge controller should come on — showing that the panel is charging the battery.

Next, you need to test the inverter.

1. Hook up the red and black cable the inverter came with on the inverter terminal, and hook the other end of the cables on the battery.
2. Make sure you connect the positive cable first.
3. To test the inverter, switch it on and plug in a home appliance with a decent load, for example, a fan.

Another component you need to test is the battery maintainer.

1. Disconnect the battery from the controller and hook the maintainer cables to the appropriate poles of the battery.
2. Again, make sure to connect the positive side first.

At the same time, you can test your surface mount contactor.

1. Plug the extension cord from the wall socket.
2. If everything is right, both green and red light on the maintainer should come on.
3. After a few seconds, only the red should remain — showing that it needs charging.

If you prefer to watch a video, here's one that shows you how you can test each of your components:

Step 3. Build the Generator

This is where you mount all the equipment and do some of the early wirings of your system.

Mark and Cut the Openings

You can use masking tape to make the initial marks. This way you can adjust them without leaving permanent marks on your case.

Measure the actual size of each hole and trace the lines onto the case. If in doubt, always cut smaller and then file or trim the opening larger if needed.

For straight cuts, use a vibrating multi-tool with a plunge-cutting blade. For the round holes, you can switch between drill bits and hole saws. 

To trim and adjust the holes, use a rotary cutting blade with a pneumatic die grinder.

You can check an article comparing Milwaukee and Dewalt power tools on Tool to Action if you need help with choosing the right power tools to use in this step.

If you prefer hand tools, you can achieve the same with a utility knife or a file. 

Mount External Components

Once you've cut the holes, test the LED floodlight for fit then line the edges with black silicone sealant to keep the box interior waterproof. Once the silicone starts to cure carefully place the light in its slot.

The 120V AC charging port comes with a rubber gasket, so you don't have to use silicone for that.

Repeat the process for the components on the other side of the hard case.

For the inverter remote control panel, you’ll need some silicone sealant. Secure the panel with self-tapping screws.

Use heavier #10-24 machine bolts to mount the weatherproof cover and GFCI outlet. Don’t bolt them yet, because you need to wire everything first.

If the solar power inverter has the peak capacity above 4000 watts, you need to use 12 gauge wire for the GFCI outlet. Always give yourself 4-5 inches of wire more than you need.

Now you need to mark and cut holes for the solar panel connection and the high-current 350A connector. The 350A quick connector is an optional feature, but it lets you use the battery with jumper cables or to daisy-chain more batteries and increase the generator power.

Finally, you need to mount the second LED floodlight on the lid of the solar generator. Follow the same procedure as used for the first one, but wait until you mount all the internal components first.

Mount the Battery

Since batteries are the heaviest components, put it in the corner closest to the case wheels. You can orient the battery in any direction, but make sure it’s well supported in the directions the case is likely to be used.

Drill two holes for the battery mount bolts as shown in the video below, but don’t fix it in place until all components are ready for mounting.

Mount the Solar Power Inverter

You need to position your AC pure sine wave inverter so that its outlets are near the GFCI weatherproof outlet and its 12V cables within the reach of the battery.

Mark the bottom hotels for the inverter and mount the hardware using #10-24 machine bolts, with washers, spring washers, and nuts.

Lastly, plug the pigtail cord from the GFCI outlet into one of the inverter outlets and the other end of the inverter remote control cable into the back of the remote switch panel.

Mount the Charge Controller and AC Battery Maintainer

The best place for the AC battery maintainer is on the back wall of the system, near the LED light that you mounted first. Then, you can connect the power cord to the female extension of the waterproof 120V AC cord socket you installed earlier on the outside of the case.

Once you have mounted all external and internal components, you need to wire them together. This instructional video below shows a detailed wiring procedure for portable solar generators like the system described here.

Things To Keep In Mind If You Use A Custom-Built Lithium Battery

If you have enough experience in DIY electronics, you can make a custom lithium battery to use with your system. There are several things to keep in mind:

Low-Temperature Cut-off or Heating System — Lithium batteries can’t be charged under 32°F (0°C) without suffering permanent damage. [3] If you use a lithium battery, find a solar charging controller with low-temperature cut-off.

MPPT Charge Controller Capable of Charge Profile Editing — Each battery needs a different max voltage. Program the MPPT charge profile parameters for the exact type of battery you plan to use.

A DIY solar generator is a self-contained and portable mini-power plant that can allow you to be 100% independent from the grid.

Over-Discharge Protection System — If you over-discharge a lithium battery, you’ll change its chemistry and damage it permanently.

High-Temperature Protection — If you plan to use the battery in a high-temperature environment, you’ll need a battery cooling system.

Cell Balancing — If you regularly charge and discharge from 100% to 0%, your cells will fall out of balance, so you need to use a manual RC battery cell balancer.

Potting batteries — Lithium batteries contract and expand during discharge and charge. So unless you compensate this with a foam pad, you shouldn't pot them.

Why Build Your Own DIY Solar Generator

Greener Than Fuel Generators

With zero emissions, solar generators are far more environmentally acceptable than those running on fossil fuels. When you are enjoying the great outdoors, the last thing you need is a diesel generator polluting everything around you.

To see a review of a portable solar generator, click here. 

Safer Than Gas Generators

Solar generators are much safer to use indoors and outdoors that those running on fossil fuels that may leak or cause a fire. 

No Running Costs

Once you invest in components and tools, your spending is done. Their components typically have warranties that go over 20 years. [4]

You Can Repair Them Easily

Unlike fossil fuel generators that use complicated internal combustion engines, solar generators are easy to repair as they are to build.

More Powerful Than Ready-Made Ones

Not all ready-made generators are powerful like the Kodiak Solar Generator. If you need more energy than an average RV owner, then building your own generators is the way to go.

DIY Gives You Pride Of Accomplishment

While building your solar generator, not only can you learn a lot about technology, but also gain a sense of personal accomplishment. You can include your spouse and kids and make it a family project.

Less Expensive Than Ready-Made Ones

If you purchase them individually, components recommended here will cost you much less than a complete ready-made generator system like this one.

FAQ

Conclusion

Sure, you can go out and buy a ready-build solar generator that meets your needs. However, if you have all the tools lying around, and know a bit about wiring, you can build one yourself and enjoy its many benefits.

A DIY generator costs much less than a factory-made one, not to mention that you can custom-choose many parts.

The whole point of building a solar generator from scratch is staying self-sufficient and proving to yourself that you can use your skills and brains to become independent from the grid.

So why don't you go ahead and build one yourself now?