Categories: RV Solar

Can My RV’s Solar System Power An Electric Car?

If you could drive a solar-powered car, would you? 

We live mostly off-grid and primarily use solar power to run our RV.  When we started talking about getting a second vehicle, it made perfect sense to us that it would be a plug-in hybrid electric vehicle that could take advantage of our RV’s solar system. 

Not only would it be a solar-powered car when using electricity, charging the car on solar would make sure we maximized the potential of our solar system!  So, we did it.  

The Chevy Volt Plug-In Hybrid

Our secondary vehicle for RVing is a Chevy Volt

This is one of the most unique cars on the road (from my perspective as an engineer).  Its unique because its both an electric car and a gas car all in one. 

Now, I know what your thinking – “that’s not unique, there are hybrids everywhere!” 

Yes, that’s true, but this is special hybrid because its internal drivetrain is in series instead of parallel.  What this means is that the car is primarily an electric vehicle, and the gas engine is just an electrical generator. 

In parallel hybrids, (pretty much all other hybrid cars out there) the gas engine is the primary driving force and a secondary electric motor assists (and can sometimes drive the car in limited situations).  The series hybrid design gives us all the features of an electric car, plus the extended range of a gas one. 

The electric side is what enables us to turn it into a solar-powered car!   

Driving Our Solar-Powered Car

Our car can go 40-50 miles on an electric charge before it switches over to the gasoline engine that provides power for an extended range.  When on electric power the car is silent and smooth with fast acceleration. 

On gas it’s… well, pretty much the same. 

Because the gas engine is just a generator that charges the battery and flows power to the electric motor the driving experience does not change except for the engine noise.  The weirdest part about driving this car on gas is that the engine speed is not directly reflected by the car speed.  Step on it to get on the highway and the car will go, but the engine might not rev up until you are up to speed. 

How We Charge Our Solar-Powered Car

The gasoline engine is basically a generator, so it can charge the cars battery if needed. But its primarily designed to be charged from an outside electric source.  Electric cars can charge from any power source that meets their requirements, and in our case we plug it into our RV.   

This is a dry campsite (no power or water but the car is still plugged into the RV

We built an extensive solar system on our RV including a large bank of Battle Born Batteries so that our RV is like a little mini power generator and grid.  This enables us to plug the car’s portable EVSE (electric vehicle charge equipment) directly into an outlet on the RV and charge the car!  

Now, in normal conditions the car takes anywhere from 8-12 hours to charge from a fully depleted battery and can consume about 11Kwh of energy.   Since we are not plugging into an unlimited source of energy, we do need to consider a few things to get this to work properly with our RV’s power system. 

The battery meter is really just a range estimate and depends heavily on how you drive, we usually get around 40-50 miles

Optimizing the RV’s Solar System with a Solar-Powered Car

Sometimes, we just plug the car charger into any old plug on the RV and that works great. However, that means there is no automatic shut-off to stop the car charging.  The problem with this is that if the sun goes down or the day clouds up the car will start drawing down our RV’s batteries. 

This is OK to a point, but if we don’t get enough sun we won’t have enough power to do other things in the RV.  

Here is a graph of what the power looks like when we are charging the car. The blue line is the battery state of charge, the yellow is solar power generation and the red bars are consumption. Notice that the solar charges up the battery to 85% then the car kicks on and the batteries slow down charging. This is how we use all the solar capacity of the system without wasting a drop of solar energy!

The Programmable Plug

We added a new circuit dedicated to charging the car to address this issue.  This circuit comes off a secondary AC output that is available from our RV’s inverter (this is the device that converts the RV’s battery power to AC power like in your home).  This circuit is programmable and we can set the limits of when we want the car to charge or not. 

We decided to control the cars charge based on the RV’s battery state of charge. 

Our Parameters

We programmed the system so that if the RV’s batteries get above 85% charged from the solar energy, we turn on the car’s circuit and start dumping the solar power into the car.  If it’s a sunny day, we make excess power even with the car plugged in and the RV’s batteries continue to climb. 

Should the day end or get cloudy, the RV’s batteries will drop. When they hit 80%, the car stops charging.  This gives us a reserve capacity of energy to use in the RV.  

Below is the schematic of our RV with the car show. Read all about it on our post about our Ultimate Off-Grid RV Solar System.

This is what the programming looks like for the car relay
Here is the schematic showing the car connected to the Inverter

What if the car doesn’t get charged?

If the car doesn’t get charged, it doesn’t matter.  That’s the beauty of the plug in hybrid.  The car is fully usable as a gas powered car that still gets pretty good fuel economy (40-50MPG).  

What about long distance drives?

For long distance drives, we change the programming of the system. When we are driving, we don’t use as much power. We dump 80% of the RV’s battery capacity to the car instead of the usual 20%.  This allows the car to drain the RV’s batteries down to 20%.   The RV recharges while drive when we aren’t using any ancillary electricity. 

When we get to our overnight spot we plug the car in and let it draw down the RV’s energy. We know we won’t need much for the next day of driving.  

We also plug the car in at rest stops when taking a slightly longer brake (i.e. for lunch).  This only adds a few miles, but every bit adds up. Usually, about 10% of our long-distance driving is supplemented by solar (if the sun is shining, that is). 

Plugged in on a rainy day at a rest stop (It had been sunny earlier in the day)

Does this RV solar-powered car thing work?

Yes, it does work! 

While the solar power we put into the car is not enough to power all of our driving needs (namely the long-distance) but it supplements our energy significantly. Most importantly, it uses all the power that otherwise would be lost from our solar system. 

Once the RV’s batteries are fully charged from the solar energy, that excess power would go unused.  With this system, we have been able to use that extra power to increase our overall fuel economy. Almost 100% of our driving over the summer was solar-powered. 

Over the entire summer (3 months) in one location we only burned 1 gallon of gas! 

Watch The Video:

See it in action over on our YouTube channel!

Are Solar-Powered Cars the Future?

We sure hope so! Having even a little bit of our driving supplemented by the sun has been amazing.

However, there is a lot to consider in trying to power a car full-time from the sun. It is completely possible to charge an electric only-car like a Tesla from off-grid solar, but the up-front cost is still prohibitive for most. As the cost of solar and electric cars continues to plummet, we fully expect to see this become a more viable option.

If you want to see someone who has done it already, check out Jason Hughes’ crazy system!

What’s Next?

We are going to continue to test our Ultimate RV Solar System, dive deeper into off-grid power, and share our findings on video and this blog.

Let us know what you think in the comments below! How else could we power this car? What questions do you have?

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Mortons on the Move

We are Tom & Caitlin Morton. We gave up the stationary life for one where we are constantly on the move. We live in a fifth wheel RV and travel with our two pups, Mocha and Bella. We enjoy hiking, biking, boondocking, videography, and upgrading our RV to suit our off-grid mobile lifestyle. Our goal is to share educational, entertaining, and inspiring content with our readers and viewers.

View Comments

  • I have been doing something similar with a Ford Fusion Energi for a couple years now. But I don't have near the solar output you have so I only get excess solar in the peak of summer. I have been doing the logic manually in my head instead of the automation you covered. I am about to switch out a Magnum inverter for a Victron Multiplus 3000va and I did not know you could use AC2 for an inverted circuit. I thought it was only for shore/generator power per the marketing material. I wasn't planning to use AC2 so I may do this. I do have a dedicated non-inverted outlet in my bay (for diesel engine block heater as needed). Sounds like I can just take the respective wires from the current circuit breaker for that outlet on the electric panel and put on AC2 on the Multi and then find the respective SOC programming?

    • Hi Kevin! That's neat that you have been doing the same! As for the Victron inverter ours actually has a second AC output because it is a quattro. With a quattro and AC out 2 yes, that is exactly how we wired it and it works great. Instead of AC out 2 a basic powered relay would work well to do the same. You wouldn't even need a full Victron system but just a battery meter that has a relay that can switch on SOC. The BMV712 has this functionality easily programmable and you wouldn't even need to switch inverters, (unless you already planned to do the victron system) :)

      • Thank you for that clarification. Yes, I already have my hands on the Multi 3000VA. Finished uping my battery cable sizes today and will start the Multi install tomorrow. Keeping my install simple with one Multi that is downstream from a 50A breaker in the main circuit panel and AC Out 1 will feed a subpanel. I don't have much experience with powered relays. Seen any example diagrams including something like that and how it integrates with the 120v circuit?

  • Good information about that "solar" car!! I am looking forward to seeing pictures and stories about your New Zealand trip though!! I bet it was AMAZING :)

    • Thanks! We are hoping to have our New Zealand adventures up by the end of the year :) It was awesome and we are excited to share!

  • Are you towing that car behind your your fifth wheel, or driving it? Is it able to be flat towed? I would love to have enough solar to power our toad.
    Another informative video!

    • Hi Lisa! We are currently not towing the car, but driving it. We currently don't have the weight capacity to tow it, but if we upsized our truck we would consider it. Behind a fifth wheel however we could only tow in states that allow triple towing. As for if it is flat towable, GM says NO. At least not when its off. I do think that it would be ok if the vehicle was left on, and something i would consider trying, but only while monitoring transmission temps. Lots of potential for future projects!

  • I don’t know where you live but I haven’t seen any EVs lower their prices, as a matter of fact they all seem to be raising their prices.

    • Well they still are not mass produced like Gas cars, but hopefully soon prices will start coming down. They have so many fewer parts, batteries just need to get cheaper.

  • It is interesting that I am doing just the opposite to what you are doing. I am on my fourth Chevy Volt. I have believed in this car for years now because of the ability to use almost entirely the electric motor around town getting as much as 4,000 miles on one 8 gallon tank of gas.

    In my case, I have a trailer that I rent out on Outdoorsy but that sits in storage when not in use. Every time that I go to clean or do other things in the trailer, the battery is dead.

    The first thing that I did was to install a trailer plug in my Volt with only the power and neutral so I can charge my battery from the Volt.

    I also have a 2000 Watt inverter that I have used to power the minimum necessary items in my house during hurricanes (I live in Florida). I have been able to power my refrigerator, freezer, a small roll-around air conditioner, TV and other items in our bedroom to survive when the power is out. My test produced 26 hours of power using the Volt battery and running the gas engine. Much cheaper and easier than a generator.

    I am now using my inverter which is attached to my Volt 12 volt battery to power my trailer. This charges my trailer battery and I can run lights, slide-outs and even the smaller of two air conditioners from this inverter power supply.

    My Volt is charged from a 10 KW solar system on the roof of my house so I am indirectly powering my RV from my home solar system.

    • No way! We have heard of people doing this with the Volt. My only concern is in the long term load on the volts DC-DC converter, but it doesn't seem to be a problem. What a great way to use all that battery capacity! 26 hours, That's amazing! Thanks for your comment.

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