Solar PV on electric cars

[tautech]

To return to wraper's stupid statement, we now have a multitude of gubbermints promoting/subsidizing the adoption of EV's in the name of protecting the planet from further pollution and yet they fail to comprehend the incorporation of PV into the roof of an EV can offer some free mile/km without any further input of fossil fuel generated power and/or reduce the full impact on the power grid if the only method to charge an EV was to plug it in.

Those that set the path we must live by and travel down are the really stupid ones for missing such an opportunity to make a further but admittedly small real difference.

[bdunham7]

I'd say cost is everything to most drivers. If you look carefully then you'll see that the market for EVs are artificially created by government incentives (even in China where it is easier to get a permit for an electric car compared to an ICE care). Take the incentive away and sales drop to zero. In the Netherlands the sales of the Tesla Model-S went from about 2000 a year until 2018 to 99 in 2019 (so far). 2018 shows a very large sales peak due to the government incentive being stopped in 2019. Other higher end EVs like the Jaguar I-pace show similar trends. People aren't buying EVs because they like them but because they want to drive around cheap due to the government incentives.

If cost is the main concern, then Tesla drivers must be bad at math.  As I said, it is much, much more expensive to drive a Tesla than an equivalent-sized Honda.  People may indeed respond to incentives, but that doesn't mean that the cost is actually lower.  Can you say that someone who is willing to spend $50K extra to get a $7500 tax break is "cost sensitive"--or is it something else?  Among EV owners I know, the only cost sensitivity is a form of self-delusion that was needed to talk themselves into an expensive and unnecessary purchase.

In the Netherlands EVs primarily get bought as corporate lease cars. Employers pay a monthly fee to make a car available for the employee. Depending on the position of the employee there is a certain budget. The employee gets tax added to the income which is a certain percentage of the price of the car. If the tarif is low the employee pays less compared to an ICE based car. Starting from 2019 the low tarif has been cancelled for cars over 50k euro. Next year the EV tarif is increased to 8% (was 4%) and the maximum price will be 45k euro. The low tarif costs too much money already so it had to be changed.

Do keep in mind that you folks living in places like the Netherlands and Belgium, and so on, are living in a different world than the US in some ways.  For example, in California fuel is expensive and we whine if it hits the equivalent of 0.80 Euro/Liter.  The tax incentive on a $100K Tesla right now, IIRC, would be $3750.  That is less than half of the sales tax that would be collected at purchase.  If these consumers are cost-sensitive, they surely aren't rational about it.   The incentives have been greatly reduced--we got a total of $10,450 on our EV--and are income-restricted in some cases, but the cars are still selling.  If the incentive were a more significant part of the cost, then of course I'd expect it to have more impact.  Our EV (Ford Focus) started with a sticker price of $41K, but due to rebates, cost reductions, tax incentives and random cash, ended up with a net cost of under $15K. Yes, that made a difference in the purchasing decision!  For Tesla though, the $3750 doesn't even offset the sales tax, let alone the much higher insurance and maintenance--yes maintenance!  The tires alone on some models would exceed many people's driving budget.

 https://insideevs.com/news/357565/ev-sales-scorecard-june-2019/

[hendorog]

That only works if you have a roof to put panels on. That is a small but significant detail.

And the more I think of it the better I like the idea of an EV which at least covers the self-discharge of the batteries by having a small solar panel on the roof. You can leave it parked with a nearly empty battery without needing to worry about the batteries getting drained completely.

That is a nice benefit.

[bdunham7]

To return to wraper's stupid statement, we now have a multitude of gubbermints promoting/subsidizing the adoption of EV's in the name of protecting the planet from further pollution and yet they fail to comprehend the incorporation of PV into the roof of an EV can offer some free mile/km without any further input of fossil fuel generated power and/or reduce the full impact on the power grid if the only method to charge an EV was to plug it in.

Those that set the path we must live by and travel down are the really stupid ones for missing such an opportunity to make a further but admittedly small real difference.

Go ahead, do the math and cost out the project.  I sort of did and quickly realized that even with 1000 free hours of my time, it was a colossal waste of money and resources.  Do some actual estimates using real measurements, data and a BOM of things that actually exist.  Keep in mind that most of the off-the-cuff approximations in this thread are wildly optimistic--even Toyota in their example using gold pressed latinum/unobtanium alloy 34% modules are only netting 860W at most (if I read that right). 

Nobody here is failing to comprehend the wonderfulness of the idea of a self-charging electric car that just has to be parked in the sun and you can drive it for free.  I'll buy it if you make it cost effective.

[james_s]

The people for whom EVs are against their religion will never be convinced, but several of my friends and family members have EVs for commuting and local driving and the #1 thing they all talk about is how great it is to not have to go to a gas station and fill up the tank. They all plug the car in when they park in their driveway, carport or garage and by the next morning it's fully charged and ready for another day just like their mobile phone. It would be a huge incentive for me too as I hate having to remember to go out of my way to fill up the tank when I'm getting low but ultimately for my own use case a conventional car is a better fit. If I were still commuting to work by car I'd seriously consider picking up a used EV commuter but I bus now so it wouldn't make sense.

There are many millions of people for whom a small EV is an excellent fit to their needs though, people who commute <50 miles round trip each day and have a driveway or garage to park in at home where they can conveniently plug in and charge and a second car in the household for the occasional longer trips.

Even so, solar panels on the car don't really make sense in terms of propulsion, but it could be nice for keeping the AC going when one is forced to park in the blazing sun. It's no fun to get into a scorching hot car and it's not good for the interior either.

[tautech]

Nobody here is failing to comprehend the wonderfulness of the idea of a self-charging electric car that just has to be parked in the sun and you can drive it for free.  I'll buy it if you make it cost effective.

Cost effective is 100+ yrs of ICE development.

[james_s]

But you presume everyone owns a roof to place PV panels on.

Of course not everyone owns a roof, but as with most things there is no one-size-fits-all solution. If you don't have a roof then obviously having your own solar installation on the roof is not going to work, but there are hundreds of millions of people who do have roofs which are potential prime locations for solar panels. There are also businesses and communal structures like apartment buildings where solar panels could be installed, not necessarily owned by the occupants.

As with many things if it doesn't work for you that doesn't mean it's not an excellent solution to someone else's situation and it doesn't mean it makes sense to try to shoehorn a concept (like solar panels) into a situation where it doesn't make sense (like trying to build them into an EV). If one has no suitable location to install their own solar panels and they wish to have an EV, then plugging it into the grid for charging is going to make the most sense. If eventually enough other people do who do have space for solar invest in it then the power generated can be distributed via the existing grid and it doesn't matter if everyone has it.

[james_s]

Cost effective is 100+ yrs of ICE development.

That depends on the bigger picture, when you factor in dwindling supplies of fossil fuels, the very real environmental costs and other factors there is no guarantee at all that ICE will always be cost effective, and the more alternatives we have meeting the needs of those who can make use of them, the more viable ICE remains going forward for those for which it is still the best or only suitable option. The more different options we have available, the better off we will all be.

[bdunham7]

Nobody here is failing to comprehend the wonderfulness of the idea of a self-charging electric car that just has to be parked in the sun and you can drive it for free.  I'll buy it if you make it cost effective.

Cost effective is 100+ yrs of ICE development.

The 100-year-old ICE was cost effective in its time or it wouldn't have survived.  But I only mean cost-effective compared to installing one more solar panel and adding a little battery to the car.  And if you don't own a roof, you can put it on someone elses!

https://www.energysage.com/solar/community-solar/community-solar-vs-rooftop-solar/

In all seriousness, I expect we'll see solar cells on car bodies someday.  We're just not there yet.

[james_s]

I don't think solar panels on car bodies will ever make sense. Even in fantasy land where a 100% efficient solar panel is possible the amount of energy required to propel a car vs the amount of solar energy falling on that car will never add up. There are always going to be more sensible places to locate the panels than on the cars themselves or in the roads, quite possibly two of the least practical locations ever devised.

[tautech]

In all seriousness, I expect we'll see solar cells on car bodies someday.  We're just not there yet.

Sure but don’t you ask yourself why not already ?

[wraper]

In all seriousness, I expect we'll see solar cells on car bodies someday.  We're just not there yet.

Sure but don’t you ask yourself why not already ?

Why don't you walk with solar cell hat already? It's very useful, for example you could charge your phone when alone in dessert.

[nctnico]

There are many millions of people for whom a small EV is an excellent fit to their needs though, people who commute <50 miles round trip each day and have a driveway or garage to park in at home where they can conveniently plug in and charge and a second car in the household for the occasional longer trips.

That depends very much on where you live. In the Netherlands 70% of the car owners don't have a driveway where they could charge an EV. In the cities this goes up to 80% to 90% (numbers from a company installing charging stations).

[hendorog]

There are always going to be more sensible places to locate the panels than on the cars themselves....

Interesting. Why is that?

[wraper]

The result, another ~5km of EV range charge/EV is loaded onto grids and required to be generated when it could well have been harnessed from the sun free !

If you put PV worth the same amount of money onto roof, you would get way more electricity to charge the car and power other stuff. So I can argue that this crappy use of PV takes money away from where it actually matters and basically wastes it.

But you presume everyone owns a roof to place PV panels on.

If you don't have a roof, it does not mean you must find a way to waste your money. Put solar panels instead of your windows, if you are so intended so stick them somewhere.

[tautech]

In all seriousness, I expect we'll see solar cells on car bodies someday.  We're just not there yet.

Sure but don’t you ask yourself why not already ?

Why don't you walk with solar cell hat already? It's very useful, for example you could charge your phone when alone in dessert.

Don’t get me wrong, I well know PV power has its place and that includes a big part of any green solution for our future.
Some years back I engaged a uni student needing a industry project to graduate to design and build a VCO based charge pump for a 6V 100mA PV panel to boost up to 150V into a 2200uF low leakage cap.
It took a little trial and error to optimise it as it’s parameters were set with passives but once right it could pump the cap full in seconds. Other than the storage cap it would easily fit into a matchbox and except for the cap cost under $5 to build.

I maintain EV manufacturers on the whole and the green legistrators have been stupid to overlook the addition of solar panels of some sort onto EV’s where one can only assume they’ve lost sight of the reason for their very existence, the reduction of pollution. 

[tautech]

I don't think solar panels on car bodies will ever make sense. Even in fantasy land where a 100% efficient solar panel is possible the amount of energy required to propel a car vs the amount of solar energy falling on that car will never add up. There are always going to be more sensible places to locate the panels than on the cars themselves or in the roads, quite possibly two of the least practical locations ever devised.

You totally miss the point.
The discussion relates to enhancing EV range and reducing charging costs.

[hendorog]

So, say I'm buying an EV in Auckland. One has solar panels and the other doesn't.

The one with solar panels states that it is on average, 25% more efficient than the other one, during the summer if it is parked in the sun. That statement is fair.

P.S. This isn't the final answer, its just something that has occurred to me as this thread has gone on.
P.P.S. General reminder that this thread is a puzzle. It says so in the first line of the OP. I want to see who is open minded enough to figure it out. Confirmation bias is the enemy in this thread.

[nctnico]

I maintain EV manufacturers on the whole and the green legistrators have been stupid to overlook the addition of solar panels of some sort onto EV’s where one can only assume they’ve lost sight of the reason for their very existence, the reduction of pollution. 

Short term it makes much more sense to ban inefficient ICE cars. In the Netherlands the purchase tax on a car is based on it's efficiency. For example: a Lada Niva which has a list price of 12k euro costs 49k euro (including tax) to buy in the Netherlands.

[nctnico]

I don't think solar panels on car bodies will ever make sense. Even in fantasy land where a 100% efficient solar panel is possible the amount of energy required to propel a car vs the amount of solar energy falling on that car will never add up. There are always going to be more sensible places to locate the panels than on the cars themselves or in the roads, quite possibly two of the least practical locations ever devised.

You totally miss the point.
The discussion relates to enhancing EV range and reducing charging costs.

And self discharge of EVs is a serious issue if you don't use the car that often. Money is evaporating into thin air if you park the car:
https://www.reddit.com/r/teslamotors/comments/5pd6fm/how_long_can_a_tesla_reasonably_hold_a_charge/

According to this posting the loss is about 10kWh per week which translates into 520kWh per year (that is as much as a big refridgerator!). I pay about .22 euro per kWh so the monetary loss is 114 euro per year. At fast charging stations the electricity price is likely double of that. If you own the car for 10 years then spending 500 euro on the solar roof to keep the battery topped up while the car is parked is well worth it.

[hendorog]

I maintain EV manufacturers on the whole and the green legistrators have been stupid to overlook the addition of solar panels of some sort onto EV’s where one can only assume they’ve lost sight of the reason for their very existence, the reduction of pollution. 

Short term it makes much more sense to ban inefficient ICE cars. In the Netherlands the purchase tax on a car is based on it's efficiency. For example: a Lada Niva which has a list price of 12k euro costs 49k euro (including tax) to buy in the Netherlands.

Wow that is spectacularly harsh! A Niva is only a small car as well.

In 2021, NZ will introduce a 3K NZD max surcharge on dirty cars, and an 8K max credit on clean ones at the border.

[tautech]

I maintain EV manufacturers on the whole and the green legistrators have been stupid to overlook the addition of solar panels of some sort onto EV’s where one can only assume they’ve lost sight of the reason for their very existence, the reduction of pollution. 

Short term it makes much more sense to ban inefficient ICE cars. In the Netherlands the purchase tax on a car is based on it's efficiency. For example: a Lada Niva which has a list price of 12k euro costs 49k euro (including tax) to buy in the Netherlands.

Sure but it’s a bigger picture that needs be better addressed.

[bdunham7]

So, say I'm buying an EV in Auckland. One has solar panels and the other doesn't.

The one with solar panels states that it is on average, 25% more efficient than the other one, during the summer if it is parked in the sun. That statement is fair.

P.S. This isn't the final answer, its just something that has occurred to me as this thread has gone on.
P.P.S. General reminder that this thread is a puzzle. It says so in the first line of the OP. I want to see who is open minded enough to figure it out. Confirmation bias is the enemy in this thread.

Your statement is not fair because it includes unstated and unjustified assumptions based on speculation and zero real world experience, as far as I can tell.

I'm sure you think yourself very clever, puzzles and all.  I'm amazed at the strength of opinions expressed here contrasted with scarcity and incorrectness of information.

I actually own a solar system that I designed and planned myself. to make my net electric bill virtually zero  I also actually own an electric car--which happened to be the most efficient (kWh/mi) one on the market when purchased.  I've sat down and figured out (roughly) how to implement solar panels on two different vehicles--the Focus and the old Ford Ranger Electric (pickup truck).  The Focus is impossible and the old Ranger maybe might have worked a little bit because it would have been a lot easier--it could essentially use two regular 60-cell panels cut up and reconfigured.  I ended up not pursuing the Ranger because they are scarce, old, not cheap, and I didn't need more projects (it would have required redesigning the battery as well).

My point is not that I'm smarter than you or that I know everything.  It is that this subject has been considered by many and actually implemented in few cases.  As of yet, nobody has shown me a system that has any meaningful technical advantage at anything remotely close to a viable price.  If a 5% (or less) increase in range or reduction in electricity costs is worth $5000 to you, great.  Please note that even Tesla, who are able to sell very expensive cars with expensive options, haven't offered anything like this, despite clearly having the technical capability--if anyone does--to implement car solar charging.

[bdunham7]

And self discharge of EVs is a serious issue if you don't use the car that often. Money is evaporating into thin air if you park the car:
https://www.reddit.com/r/teslamotors/comments/5pd6fm/how_long_can_a_tesla_reasonably_hold_a_charge/

According to this posting the loss is about 10kWh per week which translates into 520kWh per year (that is as much as a big refridgerator!). I pay about .22 euro per kWh so the monetary loss is 114 euro per year. At fast charging stations the electricity price is likely double of that. If you own the car for 10 years then spending 500 euro on the solar roof to keep the battery topped up while the car is parked is well worth it.

You guys are making these wild conclusions with pretty skimpy evidence.  One Reddit post?  Here's the facts:

1.  Li-Ion batteries of the kind in cars generally don't self-discharge very much.  Rather they are discharged by the car using power to do things when parked.  As stated right in the response you are cherry-picking, this is very simple to change--it's just a setting.  Sort of like shutting your computer down as opposed to putting it to sleep.

2.  I don't own a Tesla, but my car doesn't lose ANY significant power from the main battery when parked, even if I leave for a month.  In fact, I generally try to leave it partially discharged if it will be parked because it is less stress on the batteries if it gets warm out.  This is a design feature where the main batteries are completely disconnected when the car is not running and all power is drawn from the accessory battery.  Some cars actually have a small panel to keep the accessory battery charged, which is a gimmick but one I do like.

3.  That solar roof is going to cost you 5000 Euro, not 500, if you want even so much as a peak kilowatt out of it.  And for that you'll need a large car to boot.  You might do a bit better if you could park the car on an elevated ramp facing south with an inclination equal to your latitude, but I'm sure you'll agree that is not a generally practical solution.

Seriously, I'd love a solar roof for an EV.  I"m not some diesel-loving anti-EV fanatic. I looked into it.  Many other people with a lot more knowledge and capital than I have done so as well. Right now it is somewhere between 8K television and supersonic commercial air travel--yes it can be done, but it isn't economical or practical. I'd be happy to be proven wrong--make one! 

[wraper]

Wow that is spectacularly harsh! A Niva is only a small car as well.

Yet eats fuel like a tank.