About Solar Car Battery Chargers

Solar Car Battery Charger


Noel Joseph
August 17, 2021

Solar power isn’t exactly a finite resource; it’s everywhere, we just have to be able to harness it.

You’ve already made the switch to an electric vehicle, but now, you can take your environmental progress one step further by getting a solar car battery charger, and becoming even more energy independent.

But what is a solar car battery charger?

It sounds like some fancy device, but it’s essentially just solar panels that you can hook up to the inverter in your electric car, and dump all that juicy sunlight energy into your battery to be used on the road later.

Let’s take a look at everything you need to know.

What is a Solar Car Battery Charger?

charger connected to car battery

Like I said, it’s basically a solar panel that you can charge your car with… with some caveats, of course.

You don’t just want to get a standard 5V solar panel with miniscule wires running down your car. Instead, you want to install a permanent solar car battery charger.

This can be achieved with a bit of ingenuity and making sure your wires run the right way, and permanently attaching solar panels to the roof of your car so that it charges when you’re not using it.

I emphasise on not using it, because until the Cybertruck from Tesla, there are no solar panels that charge your car while you’re driving. The only major benefit you have while driving is regenerative braking, but of course, neither option is enough to charge your car all the way.

Solar car battery chargers slowly inject more energy into your car’s battery through the inverter. You’re relying on solar energy, and with the current efficiency of solar panels (which we’re going to get into in a little bit), you’re going to have to give it some time.

These aren’t miracle solutions, but they’re ways to lower energy costs when you charge up from your home, and ways to avoid needing a Supercharger on your way home from work when the line is pouring out into the street.

On average, it takes up to 40 hours in ideal conditions (bright sunlight, little to no clouds) to fully charge a car battery. We know you don’t have that much time, but what if you got 8 hours of ideal conditions while you’re at work? That’s a good 17%-ish of your battery life, which is better than nothing.

How Does a Solar Car Battery Charger Work?

solar battery charger and how they work

Solar panels convert sunlight into energy through photovoltaic panels. Electrons hit solar panels, and shake loose (quite literally) from their atoms.

These flow through a circuit and create electricity, and because there are multiple entry points for electrons on a solar panel, you have numerous points where electrons flow freely.

These all travel through a power cable to an inverter, which turns that solar energy into actual electricity. Inverters may exist within your EV vehicle, or they may be housed in the solar panel (depending on the size, this is usually the case) similarly to home solar panels.

Either way, the solar energy eventually runs to your battery, and is stored there in the same way that a Supercharger or home-run electricity is. It comes in slower; a Supercharger is titled as such for a very specific reason.

If you’re not going to use a more reliable, fast-acting form of charging your vehicle, it will take days to fully charge your battery with solar battery panels. They’re a good idea to supplement your vehicle, but not a long-term, end-all solution.

Is it a Reliable Source of Energy?

how reliable are solar chargers

Solar panel car battery chargers are reliable, but only as reliable as any other solar panel out there.

You have to realize that the most powerful solar panel in the world only has a conversion rate of 22.8%, that is to say, only 22.8% of all the energy that goes into the solar panel actually becomes usable energy.

That’s a big leap from how bad it was years ago, when 0.5% was the threshold. PV panels are useful, they are reliable, but they’re not all-in-one solutions. You need time and the weather on your side to really get the most use out of them, so let’s break down exactly how you can make them the most efficient sources of energy for your car battery possible.

  • Buy More Than One: However many your car battery can have attached at once is how many you should purchase, if your hood space allows. When you park at home for the day, lay your PV panels on the hood and top of your car, and connect them. The thing is, you have to know what kind of neighborhood you live in, or have a spot in your own gated backyard to park your car so you don’t have to worry about anyone trying to lift the panels off of you while you’re inside.
  • Follow the Weather: You’re at the mercy of mother nature on this one. There are going to be times where you don’t get as much use out of your solar car battery charger panels as you could, but that’s just the nature of solar energy in general. Your home solar panels will endure the same issues. Pay attention to which direction the sun rises and align your car and panels accordingly for the best results. Sunny, cloudless days are obviously going to work best for this, but there can still be some levels of efficiency even in cloudy weather.
  • Useful Anywhere: Running low on power when you make it to your destination? Pop the panels out and hide the wires so they’re not directly visible to passers by. You can charge your car, at least a little bit, while you spend time at your destination and get a little more juice in the battery when you come back outside.

One thing to keep in mind is that batteries need to full cycle charge, so these solar battery chargers should be used with the expectation of fully charging your battery in most cases, such as if you’re done for the day and want to charge it at home.

It’s okay to add small bursts of energy here and there (after all, it’s better than getting stranded with no life in your battery and calling a tow truck), just be sure to use it sparingly as a last-ditch effort.

Is it Worth Buying One?

Sun protection with solar charger

Let’s look at it this way. This works for both environmental and financial reasons for owning an electric car, by the way.

If you plug your car into a home charging port, you’re using whatever initial power source is funding that outlet. Now, if you’re off the grid or you have a completely solar-powered house, then good for you. That’s fantastic and there’s no reason to not charge your car from your home.

But if your home is being fueled by electricity from a power company, and they’re using coal or gasoline to make that electricity, then are you really doing anything positive for the environment? It’s a step in the right direction, but it’s also still chained to dirty energy sources.

Financially, if your home is run exclusively by solar power, you have nothing to worry about. You’ve already invested in the solar panels, you may as well use them. If you pay an energy bill, you’re basically trading what you pay in gas for a slight spike in your electricity bill.

Is it as bad as the price you pay for gas? No, not at all, but it’s still not the best financial motivator. If you have a solar car battery charger, you spend money once, and will likely have it for 5-10 years (longer with TLC).

You could save years off of the equivalent cost of running electricity from your home. Not to mention the fact that the price you pay for PV panels now will be cheaper than what they’ll be in a decade as shortages come through, let alone the cost of electricity ten years from now. It’s an investment.

Solar Power for the Future

Solar power is the future, and we’re seeing many electric car recharging station utilize solar energy over other energy sources, which means that sometimes it’s 100% safe for the environment to run your full EV car.

Every time that you use your solar panels to recharge your car battery, you’re not only keeping the lines at the Supercharger a little bit thinner (and let’s be honest, we don’t want to sit in those lines either), but you’re also contributing to the future of solar energy. These panels can literally last you a lifetime with proper care.


Noel Joseph

Noel Joseph has been in the world of motor vehicles for a long period. Currently, he is enthusiastic about Electric & Hybrid Motors and is an independent researcher. He advocates for a clean and sustainable future and envisions utilizing his years of experience in mechanical engineering. His new venture here at CompactPower.com is to organize and simplify knowledge on Electric vehicles. He wants to build a space where people can talk about EVs and associated technologies with freedom.