#Vanlife: Can you charge an electric vehicle with rooftop solar panels?

You’re not alone in eyeballing that new Ford F150 Lightning or Rivian R1T as a potential overland truck. Or the Ford Transit Electric as a custom camper van. How nice would it be to ditch the constraints of gasoline, not to mention the pollution and expense, and just escape off grid?

The trick, of course, is battery life. So, we wondered, is it possible to charge an electric vehicle off of solar panels?

The simple answer is, yes, you could charge an EV from onboard solar panels.

The real answer is, no, it’s not practical yet, because math. It would simply take too long to charge up your camper van or overland truck to the point where it could drive any useful distance. But why? What would it take? And how far off are we? Let’s find out…

Disclaimer: I am an amateur mathematician and electrician at best, but I had smarter people fact check this story, and for all practical purposes, it accurately explains the concept.

Can solar panels charge an electric vehicle?

rivian R1T with offroad package

Rivian sells an offroad package, but nothing for solar charging.

Let’s use the new F150 Lightning with the extended range battery as an example, and see what it takes to charge it up. This model includes Ford’s 80-amp charging station that gets hardwired into your home’s power grid and delivers 19.2kW to the vehicle’s onboard dual charging system. It will charge the vehicle 85% (from 15% to 100%) in 8 hours. One hour of charging would give you about 30 miles of additional range.

math formula for determining the range of an electric vehicle based on charging speed and capacity

Here, we need a few numbers to put everything else into perspective. Ford doesn’t disclose the size of their extended range battery pack, but our back of the napkin math suggests about 180kWh. That’s almost 100kWh more than the extended pack for the Mach-E, which isn’t designed to carry large payloads.

Problem #1 – Basic chargers are slow.

estimated charging time for Ford Lightning electric truck

Ford’s EVs all come with a standard 32-amp Mobile Charger that plugs into any 120V or 240V outlet, so you could charge it up at your friend’s house. Buuuut, on an upgraded 220-240V home outlet, that Mobile Charger is only putting out 7.68kW, and Ford estimates it would take 19 hours to go from 15% charge to 100% charge. One hour of charging at this level would net you about 13 miles of range.

Problem #2 – They’re even slower off standard outlets.

If your friend doesn’t have a 240V outlet, or you haven’t installed one at your home, that charger is pulling from a standard U.S. 110-120V outlet, kW output drops to 3.84, but charge times will likely more than double. Those 19 hours become about 40 hours or more.

Probably a lot more, because Ford says its Mobile Charger will add about 20 miles per hour of charge to the smaller, lighter, and more aerodynamic Mach-E on a 240V outlet, but only about 3 miles of range per hour on a 110V outlet. So, optimistically, let’s say the Lightning would get 2 miles per hour of charge on a standard home outlet.

Problem #3 – Solar would be way, way slower.

 

wiring diagram for how to charge an electric vehicle with solar panels

If it worked at all.

This is where it gets complicated. Even with the lowly 120V output, the Mobile Charger wants to pump out 3.84kW. You’ll see why this is a problem in a second.

Best case scenario is we have a quad-cab truck with topper and four 100W Renogy solar panels on board. They’re putting out 400W, running through a power control box to charge your accessory 12V battery bank. This is the typical setup for overland vehicles, RVs and camper vans with solar, so let’s use that for this example.

Those auxiliary batteries are standard 12V DC deep cycle batteries, though…not your EV’s main batteries. So to get their power to your EV’s Mobile Charger and then to your EV’s batteries, you need an inverter to convert to 110V DC in order to plug your charger in and then plug your vehicle in.

Remember, Ford’s Mobile Charger on a 120V outlet wants to output 3.84kW. That’s 3,840 watts! Most inverters are rated to 1,000 to 3,000 watts. So right off the bat, you may not even be able to get the equipment to make this work.

But let’s say you can, it still wouldn’t matter.

Our example solar is only generating 400W of DC power. Assuming it only loses 20% being converted to AC as it goes through the inverter that the Mobile Charger is plugged into, that’s 320W, or less than 10% of what the Mobile Charger wants.

Assuming it even works at that minimal output, your 40 hours of charge time just went to 400+ hours. Your extra 2 miles of range per charge-hour dropped to 0.2 miles.

Considering it would take those same 400W solar panels about 2-4 hours of decent sun to fully charge one 200Ah 12V auxiliary battery, and that any attempt to charge your EV off that battery would suck it dry so fast as to be pointless, I won’t even do the math to sort that scenario out. But I used Renogy’s Solar Sizing Calculator to see what they’d recommend for a system:

how much solar panels it would take to charge an electric vehicle

 

So, just to power Ford’s Mobile Charger at the minimum level under ideal conditions, you’d want around 24,000W of solar panels and about 125 deep cycle 12V batteries.

Couldn’t I just hardwire the solar panels into my EV’s battery bank?

Wouldn’t that be nice? Maybe someday, but for now we don’t know of any EV brand that makes an adapter to go from solar directly into the car’s onboard charging system. That said, we hope someone’s working on a solution. Even so, as the math above shows, the gains from even a 1000W solar system would be trivial.

What about using a generator?

Bringing along a small generator would certainly charge your auxiliary batteries faster, and if it had a built-in inverter that you could plug your EV’s mobile charger into, then you’d gain some efficiencies. But, even assuming the generator pumps out reliable 110V power, you’re still looking at only gaining about 5 miles of range for every hour of charging.

And from an overall efficiency standard, that translates to probably about 5-10 miles per gallon of gas used by your generator…which is, honestly, on par with what many RVs and non-diesel camper vans get in the wild. Except that your vehicle is probably emitting far fewer pollutants than a generator. And less noise. And then you don’t have to bring a generator.

Bottom line

Yeah, it’s probably not going to work. Yet.

charging an e-bike off of a camper van battery bank from solar power

OK, but can I at least charge my e-bike with solar power?

Sure, but you’re still going to have to plug the e-bike’s charger into something, which means an inverter in your van or truck. And that inverter will be pulling from the battery bank that’s charged by your solar panels.

So, let’s use Bosch’s 4A standard charger as an example. Most camper vans and overland vehicles use 12V deep cycle AGM batteries, which typically have 100Ah capacity. That means you could get about 25 hours of charging (enough for about five full charges of Bosch’s Powertube 500 battery) from a single AGM battery…in a perfect world.

The problem is the inverter is inefficient, so you won’t get that many charges. And to charge a single AGM 100Ah battery, you’d need a decent amount of solar, and most vehicle’s roof top solar arrays aren’t going to keep up with that draw. So, you’re literally draining your battery bank faster than it can recharge.

So, yes, you can charge your bikes off your camper van’s auxiliary battery, but it’s going to dramatically cut down on what else you can do with that power.

Stay tuned…

So, while you can’t recharge your electric vehicle from roof top solar panels, we’d still definitely recommend adding solar to your camper van or truck, for reasons we’ll cover in future articles. In the meantime, listen to our deep dive into solar, batteries, and power systems for adventure vehicles in this podcast interview with VanDOit!

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Collin S
1 year ago

Engineering explained did a really good nitty grity on this about a month ago: https://www.youtube.com/watch?v=7L1_zvqg73Q

TL:DR, same conclusion.

maxim
maxim
4 months ago
Reply to  Collin S

I have hybrid, and solar panel on roof, if can give me extra 4 kilometers of free drive, it is a lot better, then using petrol engine to charge battery with this same amount of energy. PS cells used in cars are also wasting power as heat, then slowly charge from solar panels are still better solution, then using engine and fuel. engine is charging with a lot of higher power, and some of that power is wasted as heat, when using solar panel with low current, cells are charging better and les heat are produced. PS, heat for cels are bad.

Seraph
Seraph
1 year ago

You could skip a lot of those connection points if you had an official solar charger integrated into the vehicle’s chassis, like the panels on some of the Teslas. I’m no mathematician but I would put money on better charge efficiency if you could integrate the solar panels somehow.

Frederick E. Frederickson, PHD
Reply to  Seraph

There are no integrated panels on any current Tesla vehicles. They have been suggested/hinted/teased for the Cybertruck, but that’s not something you can buy right now.

Benys
Benys
1 year ago

Another relevant way to anwser this question is to calculate the maxium power you can output from a given surface.
Let’s say the roof, hood and half of the sides of the car, and see how many hours you’ll have to wait to be able to do a few miles, or a what speed you can drive in theory.

Spoiler : It’s not much, even if you consider “perfect” electronics.

Collin S
Collin S
1 year ago
Reply to  Benys

See the engineering explained link I posted above. They do the calculations for a tesla 3 assuming all sorts of different factors (100% efficiency on an optimal sunny day, then again with real world solar panel efficiency and a factory to compensate that its not always perfectly sunny). In perfect 100% make believe world, maybe… but in the real world, absolutely not.

Benys
Benys
1 year ago
Reply to  Collin S

Good math and nice explanations. I’m quite surprised by the results, it means that a fully autonomus house with car-charging capability is totally doable in a lot of place…with solar pannels only !

I don’t feel like the first part is relevant, they could have skipped it to the point with the actual power on the ground, and do the perfect world hypothesis math from that point.

Maps of solar potential are easy to find, and wind data is also quite easly available…
Their may be a potential market for fully autonomus vans/trucks with deployable solar panels and a small windmill, the tech seems to be here.

Kay Jean
Kay Jean
2 months ago
Reply to  Collin S

What if we consider the typical job commute… cars are sitting in the job parking lot for 8+ hours each day… that has a benefit to charging availability when commuting each day ?

Paul Johnson
Paul Johnson
16 days ago
Reply to  Kay Jean

Not if you have to travel any distance to work, or are carrying a load unless you can plug into the grid you still won’t get enough charge if relying on solar at home, there may be enough hrs in a week or two but not a day, plus we do get cloudy and rainy days.
It’s just not viable

Gerhard
Gerhard
1 year ago
Reply to  Benys

Here you see the actual technical maximum
https://en.m.wikipedia.org/wiki/World_Solar_Challenge

Jo Weick
Jo Weick
27 days ago
Reply to  Benys

For vehicles on the road, this is relevant. But in a camping situation, you can set up portable solar, have lots more lithium storage or may be towing a trailer with roof top real estate for 2kw of solar.

Paul Johnson
Paul Johnson
16 days ago
Reply to  Jo Weick

It takes 7hrs to charge a 48volt E Bike on mains, just an E Bike, the car charging would only work if you didn’t use any power to use appliances and with current technology it would take 8hrs of continuous sun for at least 6 weeks to get any useable range.

Matt
Matt
1 year ago

Love content and articles like this. I don’t have a van, electric vehicle, or e-bike, but with the growth of these markets, figuring out how to harness solar power is only becoming more and more relevant. And while a few solar panels on your vehicle isn’t as compelling as one might hope, I can only imagine that the technology will improve in leaps and bounds over the coming years.

On final thought: with everything going electric, I really hope that some of the fundamentals of electricity and batteries becomes a more common topic in education curriculums. I got some brief exposure in school via electives, but see this as table stakes for all of us moving forward.

Frederick E. Frederickson, PHD

The 3.84 kW sited for the Ford mobile connector is a maximum on a 110v 15amp circuit. It will work on a slightly lower voltage and can draw less current, but that will only reduce the charge speed further. The calculations here would be the best possible for a 110V circuit.

oldfieldcycles
1 year ago

there were some people doing a trip from Alaska to Argentina in an EV van with a solar array. it has a lot more panels and it only gets 100 miles of range, but they were able to do it with a lot of compromises and a lot of infrastructure to make it work. it takes them at least 2 days to charge up their pack. https://www.youtube.com/watch?v=pcj2lQwH7N4

Ron
Ron
1 year ago

It’s also worth remembering that if your power grid is primarily driven by nuclear or coal, your electric vehicle is therefore primarily powered by those as well.

bikersly
bikersly
1 year ago

In the comments of the Engineering Explained video there is mention of Aptera working on solar charging vehicles. I can also think of another: the lightyear 1: https://www.forbes.com/sites/afdhelaziz/2020/11/19/why-lightyear-is-the-most-game-changing-car-company-on-the-planet/?sh=5160ae8a71ee

not saying this is ready for prime-time, but the concept is definitely under development.

@ron, correct. which is why we need to look at phasing those out too.

kudos to you guys for bringing this up on a bike site!

output claculated waaaaaaaaaay to low.
output claculated waaaaaaaaaay to low.
11 months ago

Is noone going to adress the fact that the solar panels are weak as shit? 100w per panel is a joke in todays standards, heck even Renogy has panels with 320W per panel. Sunpower has a panel with 400w (optimal) output, quadroupling the calculated output. How can someone take this serious with such a huge oversight.. considering you could also cover the bed and hood of the car with additional panels with little effort, sure you might need to use two flexible panels for the hood but still, that would get you around 200w extra output from the hood alone.

Aaron
Aaron
7 months ago

A 400 watt panel takes up almost as much space as 4 100 watt panels…you realize that right? that solar panels aren’t magic?

Paul Johnson
Paul Johnson
16 days ago

But that will add way more weight and further reduce range. There’s always a trade off, no such thing as a free lunch

Katuya A
Katuya A
10 months ago

I saw a Japanese You Tube that charges an electric car with a DIY solar panel.
https://youtu.be/LGfsXjvi6LE
It would be realistic to install them on the roof of a carport or garage and charge them.

Timothy Greenwood
9 months ago

Hi, Tyler Benedict ! The Sion car ( not the Toyota, and no “c” in the name) from Sono Motors uses in the body skin solar panels to get a few miles a day contributed to the total charge in the car . Solar onboard charging? yes! https://sonomotors.com/en/sion/ NOT a full charge every day, but a contribution of a few miles. more like grazing instead of gorging from the charge perspective. – USA based inventor gets a few miles every day added to his Prius with a charging system he invented. https://www.youtube.com/c/InnovativeSustainableSolutions

Jay Carrigan
Jay Carrigan
7 months ago

Why can’t the use small wind turbines in the grill that spin as u drive at a 3 to 1 ratio to charge as u go, n if u can’t drive n charge on the same cell then have it alternate between cells? I’m not a engineer, but it honestly doesn’t sound like it would be that hard with today’s technology, n so far no one has given me a straight answer on why u can’t! So I’m beginning to wonder that the automakers ate full of it, n just want to make more money off u using there chargers!

Aaron
Aaron
7 months ago
Reply to  Jay Carrigan

You would get less energy from the turbine than you expend overcoming it’s drag. What you are describing is free energy. There is no such thing.

Marko
Marko
3 months ago
Reply to  Jay Carrigan

by your statement alone I can see you are defiantly not an engineer, you cant create energy, only change its state and there are always energy lost to by products (normally noise and heat) so for the energy you put into moving you would get very little back from the turbine and just run the battery flat quicker.
you could use a turbine when stationary to harvest wind energy to recharge, but would need to store it for driving.

Rufus Dufus
Rufus Dufus
7 months ago

(deleted). 19.2kW x 8h is NOT 153.6kW. It’s 153.6 kWh or 153.6kJ, not kW.

Thomas
6 months ago

Can EV be charged at a Solar DC level to eliminate batteries and Inverter?

Jessie Jane
Jessie Jane
4 months ago

So is this based on the 400 watt cells being sold today or the 100 watt cells being sold yesterday? Additionally, your figures except for energy will not hold true once solid state batteries hit the market in the next year or two. 400 watt cells, solid-state batteries game-changing combination.

Mtrgrrl
Mtrgrrl
4 months ago

Why bother using an inverter? Go solar straight to the car batteries.

Pete Za
Pete Za
4 months ago

You can get a boost converter for like $20-40 and boost the ~22vdc from a single Renogy panel up to the 54vdc needed to charge your e-bikes directly from the sun. It won’t charge at 4 amps like the stock charger unless you gang a few panels together, but you can do it, and it’s relatively efficient compared to going through the inverter and house batteries. If you aren’t riding the bike for the day, it should fully charge up from empty while you do other activities if the panel has good sun exposure. Technically, you could also use that same boost converter to boost from your 12v bank up to the e-bike voltage and be more efficient than the inverter as well.

momo
momo
4 months ago

Alright… it’s been a year — a 3500 mercedes cargo van has the roof surface area to handle 5 rows of 3 SISHUINIANHUA 1000watt solar panels — with dimensions of 120x55cm a pop
https://www.amazon.ca/Flexible-Waterproof-Outdoor-Rechargeable-System/dp/B09SZ2TSPV/ref=asc_df_B09SZ2TSPV/?tag=googleshopc0c-20&linkCode=df0&hvadid=578917424132&hvpos=&hvnetw=g&hvrand=9267997072513352869&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9061009&hvtargid=pla-1854236052232&th=1&psc=1

that’s 15 panels creating 15000 watts of power altogether. hook them up to a Powernen 15000W Smart Power Converter 12V/24V DC to AC 220V Solar Inverter
https://www.amazon.ca/Inverter-Converter-Inverters-Display-6000W-12Vto220V/dp/B0B3DLN23Z/ref=sr_1_6?crid=29P2VA7X31LOH&keywords=solar%2Bpower%2Binverter%2B15000&qid=1657737148&sprefix=solar%2Bpower%2Binverter%2B15000%2Caps%2C63&sr=8-6&th=1

and you can basically get a full charge in maybe 10 hours if it’s in the sun — completely off sunlight for a $10,000 set-up

Someone check my math

maxim
maxim
4 months ago

O my god, I stopped reading this article after I see drawings about solar panel, power control, batteries, inverter, and connecting to ev charger… oghh, that’s true, is waist of energy, time to make, and big cost.
Yes it is posible to do so, and it is much simple. it is possible to connect solar panel to car battery straight forward using diodes, but then cuestion is, when to stop charging Your car battery if acus are full. there must be also a controller to disconnect cells which are fully charged. and that’s all. no complicated drawings to ev charger. for me, I have toyota auris hybrid, and I see how cels are constructed, and for me using 50W of power from solar panel would be nice. it is in full sun 5A. my car for driving is using between 10-to 20A, sometimes 40A if I am driving faster, but usually it is 20A.
My car is standing on parking minimum 8hours, and from work to home i have 15min, that means, on 8 hours charging with 5A, i can get maximal 40A per 8 hours, that is enough to save extra power, rather to use engine to charge that batteries anyway.

Scott Weathers
Scott Weathers
3 months ago

What about and alternator generator that would charge the EV‘s batteries similar to a regular alternator on a car but with much more output. seems like it would work unless there just isn’t an alternator big enough to keep the EV‘s batteries fully charged like it does a regular vehicle battery.

David Thompson
David Thompson
28 days ago
Reply to  Scott Weathers

Because the alternator is another load on the system which would deplete the battery charge faster, and not be able to replenish at the rate it depletes.

Scott Weathers
Scott Weathers
3 months ago

Well with my idea if it would work the car would charge itself as it ran similar to a regular automobile you wouldn’t even need solar power?

George
George
2 months ago

Your solution….Aptera is the most efficient Solar Electric Vehicle that requires no charging for most daily use……https://aptera.us/