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Electric Vehicles are a key part of our tomorrow and how we get there. If we can get all the fossil fuel vehicles off our roads, out of our seas and out of our skies, we'll have a much better environment. This community is where we discuss the various different vehicles and news stories regarding electric transportation.
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Probably easier to hook those panels up to your balcony. You'd charge at home anyways, right?
Are those 15 km under ideal conditions? With static panels you can control those easier. On the car the panels will usually have the wrong angle. Plus the added weight and wind resistance further decreases the effective range they provide.
plus vibration and potholes and all kinds of weather exposure.... all those teeny tiny fine wires connecting each cell up.... would not expect off the shelf solar to cope well with all that.
The big question is how will you integrate that into the van's power system? I doubt four panels will make enough voltage to work with the stock charging system, and even if it did, there will be interlocks preventing you from driving while charging (as it presuumes you're at a stationary charging point).
They could connect it to a "solar generator" and L1 charge from that. That's nowhere close to seamless and would be pretty annoying for daily use, but not terrible while camping.
Yeah, that could work. But definitely going to need some intermediary tech, and integrate it.
Plus there are probably some efficiency losses in an inverter taking the DC output of the solar-charged battery and generating an AC waveform expected by the car's ICCU, to be redirected into charging the cells of the actual car.
The problem with putting high output panels on a vehicle is weight and durability. The panels plus equipment could add more than a hundred kilograms, ruin the aerodynamics, wear the vehicle out faster, and installation would require heavy modifications inside and out. So your efficiency return would be much less than you think.
Could you do it? Sure, but you would need to be willing to sacrifice a vehicle because no one will want it after it's done, except maybe for someone who wants something to tinker with.
Just a guess but manufactures don't build solar panels into cars for a few reasons.
-Vehicles tethered to a fuel source like gas or electricity keeps people spending money and companies and governments love it when people spend money.
-The vehicle would need to be designed around the solar panels which makes design more difficult and costly.
-The solar panels could act as a back up for running the computer and accessories but wouldn't ever generate enough power for driving, so why bother when they can just make the main battery a little bigger.
This is a very common idea when it comes to EVs, and the conclusion we've come to time and again is that the juice isn't worth the squeeze. Even overcoming technical hurdles like how to actually get the power from your panels to the batteries, and installing the panels into the van so it is still aerodynamic, you still have the problem that you simply need more panels in order to get a non-negligible amount of charge in a reasonable period of time. Your calculations are assuming the panels produce 800W of power all the time - but that is the maximum amount they can produce. As soon as anything changes to make power generation less than ideal - change in sun angle, dust accumulation, clouds, etc - you lose power from your calculation. And for the amount of time and money you would spend on this project, your break-even point on electricity cost savings would likely be infinite.
For reference, this is what a solar car designed for the purpose of running off its own electricity looks like:
https://en.wikipedia.org/wiki/Tokai_Challenger
The solution is to simply charge the car from your home solar array. Hopefully your utility/government pays you or gives you credits for excess power you generate, so you can generate during the day when you drive and charge at night. Or you could get a home battery bank. If you don't want to do a full home solar install, you could build a car port out of 2x4s and mount a few panels on top of that as a DIY project.
I came up with the following. 3 600w/800w panels which generate roughly 15km of range on an average eu day, would fit on top.
this is southpark underpants gnome level planning, i like it :)
for 2... you're going to need to need to figure out how to trickle charge a massive EV battery, you'll need to disassemble the charging infrastructure onboard the car, redesign it from scratch and build it. You'll probably need to reprogram the onboard computer as well as it will be all integrated.
OR
carry around several extra heavy 200AHr batteries in the back of the van charging off the solar, install an inverter and connect an 8A 220V charger to that :)
I'd suggest an alternative lazy approach, rather them several years learning to be an electrical engineer. Install panels on your roof/balcony at home and feed that into the house/grid and then just charge the car on an off peak tariff.
let us know how you go!
I came up with the following. 3 600w/800w panels which generate roughly 15km of range on an average eu day
How did you come up with that? Are you accounting for lost generation due to pointing straight up at the sky, and reduced efficiency due to increased aerodynamic drag?
There's a good reason we don't put solar on vehicles, its expensive and there's not really enough space to make much of any difference.
Looking at that roof, it looks like it's about 3m x 1.5m, for 4.5 m^2. Typical solar panel gets about 200W/m^2 at max sunlight.
So that's a peak generation of 900W. With a 24 hour day and a capacity factor of 10%, that's about 2.16 kWh of energy per day. For a van like that, with the weight and aerodynamics of a bulky solar system on the roof and the systems for storing that energy in another battery and cleanly providing that power in a way that the car charging system can accept? I'd be skeptical that's good for more than 8km per day, on a sunny day.
That peak though. Which you'll realistically never reach, much less for 24 hours...
Yeah, that's why I used a capacity factor of 10%, which is pretty normal for fixed solar panels. That should be enough to account for clouds/weather, nighttime, etc.
The spec say 1.8x3-3.5m 10% seems rather low. 8km is still great tho, i don't really need more than 30km a week.
The spec say 1.8x3-3.5m
Are you talking about the entire width and length of the vehicle? The roof is smaller than the total footprint. Especially because the width of the vehicle includes the mirrors sticking out.
10% seems rather low.
No, it's pretty high for the use case you describe. Utility scale solar with panels pointed toward the sun tends to achieve about 20-25%, with some American desert installations at 30%.
Home balcony solar tends to get 10% in places like Germany, with the higher latitude and higher likelihood of overcast skies.
Putting it on a vehicle roof would be lower than that.
So 2 kwh per day is optimistic.
i don't really need more than 30km a week.
So why buy a vehicle at all? Seems like the resources that go into an underutilized vehicle would be better used for things like paying fares on taxis.
You're better off just charging with 100% utility solar/wind from the grid and paying money for it, rather than trying to combine a mediocre solar array in a costly way that kills your vehicle efficiency.
The specs are 4.5m, I est the front is around 1m. You can put 3 or 2 1.8/1.1 bifacial cells ontop with 450w each. Thats 900-1350w peak correct? Taxis are really expensive where I live. My regular driving is just 30km but i do want the car for going on longer trips as well and occasionally heavier cargo, but than there is no house array charging possible far from home.
First, solar roofs just don't make sense. Others have covered that here, but it's better to put the solar in a way good for being solar, and leave the vehicle in a way good for being a vehicle.
Stick on solar panels on the roof would be enough to keep your fridge running if you already had a camping/power setup. But it's not enough to cover any real distance driving.
There are some portable solar panels, even ones specifically designed around EVs. But like other folks have said, it is cumbersome. They charge their own battery and then you dump that into your EV while parked. But the energy generated Is pretty minimal.
Also if you end up tacking it on top you might end up losing whatever efficiency gained from the panels to mileage sacrificed by aero loss
Unlike gas, which involves destroying your fuel source (investment).
A solar roof on a car is an investment that constantly provides consistent albeit fluctuating dividends.
Every cent counts when spanned over years. Especially when its portable.
There’s peel and stick panels I’ve seen people put on their overlanding rigs but I’m not sure they make a lot of power. That would be a better option vs a stiff panel because of aerodynamics. But converting that power to be useful to the car is another problem. It needs 220AC or some kind of medium voltage DC and it may also not move if it detects power on those inputs, for safety reasons. Car roofs aren’t oriented in the correct azimuth and inclination most of the time to maximize charging. I’m not sure the ROI is more than “fun”.
Thanks for all the feedback. I should probably clear some things up tho. First, I do not expect charging while driving. Second, I do not drive a lot in general maybe 30km a week. So it really just has to generate this amount for me to never bother to charge.
The aero dynamics had me worried as well, but I do not have the expertise to access this, but if you look at bikes on a car roof, it can't be that bad, right?
Aren't there solar panels that work better in bad angles? Also could one not make some mechanical setup to angle them up while parked?
I did not account for the input having to be a specific type tho. I thought you just have some battery for camping anyway. And you charge that from solar and this plugs into the regular charge input. Avoiding modifing any crazy electric tech of the car.
If I modify the car, I would do that in the interior anyways for a kitchen or bed etc.
Its not so much about recouping costs and more about the convience of waiting and getting km to drive. So it is for a nice camping van setup that also solves my regular car needs.
I do have some balcony solar and it works great, highly recommend. But its still rent and I cannot charge a car from my apartment.
