
Electric car – charged by the sun - cjbenedikt
https://www.sonomotors.com/sion/#1
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zbrozek
Cars competing in the World Solar challenge have a similar number of solar
cells. They weigh about 300 kg with occupant and have ridiculously good
aerodynamics compared to ordinary cars. Further, their cells are almost all
pointed up. Those cars manage about 600 km per day, but are also tilted
towards the sun for a couple hours a day _in addition_ to having their cells
oriented ~optimally while driving.

There's simply no way that anything even vaguely resembling a normal car is
going to have that kind of solar energy performance. Having been the team
captain of one of those solar race car teams, I long-ago decided that solar
panels are best bolted to the ground or a building and the vehicles unburdened
of their weight and fragility.

I do think cars should have a tiny solar panel built in to them, but it should
be there to offset the quiescent load of the body electronics on the low-
voltage battery.

~~~
karlding
I believe World Solar Challenge regulations [1] are now only allowing a
maximum of 5m^2 for Cruiser class vehicles (mounted to the car itself).

    
    
      +------------+-------------------+---------------------------------+
      | Class      | PV Cell Chemistry | Allowable Total Cell Area (m^2) |
      +------------+-------------------+---------------------------------+
      | Challenger | Si                | 4.000                           |
      +------------+-------------------+---------------------------------+
      | Challenger | thin film GaAs    | 3.560                           |
      +------------+-------------------+---------------------------------+
      | Challenger | multijunction     | 2.640                           |
      +------------+-------------------+---------------------------------+
      | Cruiser    | Si                | 5.000                           |
      +------------+-------------------+---------------------------------+
      | Cruiser    | thin film GaAs    | 4.440                           |
      +------------+-------------------+---------------------------------+
      | Cruiser    | multijunction     | 3.300                           |
      +------------+-------------------+---------------------------------+
    

And then a supplemental array may be carried inside the vehicle only for
charging (2m^2 for Si, 1.78m^2 for thin film GaAs, and 1.32m^2 for
multijunction). So the total area actually on the cars at WSC would be less.

But yeah, as a member of one of these solar car teams, it is hard to design a
net-positive vehicle that doesn't resemble a UFO. Cruiser class is a move in
that direction, but the most successful teams have an aerobody and chassis
optimized to be as flat as possible, to get the most out of their array.

[1]
[https://www.worldsolarchallenge.org/files/1504_2017_bwsc_reg...](https://www.worldsolarchallenge.org/files/1504_2017_bwsc_regulations_final_release_version_11.pdf)

------
diafygi
EDIT: This screams scam or at least heavily misleading.

> A total of 349 SunPower cells are producing 1,144 Watts peak at an
> efficiency of 22%.

EDIT: That's 3.27W/cell, which SunPower cells do provide. I counted the cells:

    
    
        Roof:                 114
        Hood:                  45
        Dashboard:             24
        Driver Front Door:     33
        Driver Rear Door:      21
        Driver Rear Panel:     21
        Passenger Front Door:  33
        Passenger Rear Door:   21
        Passenger Rear Panel:  21
        ??? unknown location:  16
        -------------------------
        Total:                349
    

So only, 52% of the cells will ever have the chance of being positioned
correctly. Even still, the angle of the roof cells are curved, so half of
those will not be in good positions when the hood is angled directly at the
sun.

That leaves you with 126 cells that might be positioned correctly, which means
a real world capacity of 413 W, which will result in a max range of 23 km (EVs
get ~7km/kWh). The 30km range is extremely ideal, and real world is likely
closer to 10-20km from 8 hours of solar. That's ~2km per hour of sunlight.

Anyway, parking the panels directly in the sun at the ideal angle for 8 hours
will be pretty impossible for most people. However, it might have a niche use
case for remote research stations or cabins?

Unfortunately, the marketing on this makes it seem like this would be good for
urban users, so the team appears to be heavily misleading backers (e.g. scam).
Cities are extremely bad for solar cars (all the tall buildings make a lot of
shade).

------
lumberjack
12.000/16.000€ for 120/250km is pretty good if they can manage it.

This is now solidly within affordability of everyone.

Not sure how they are beating Mitsubishi, Renault and Nissan though.

Never mind:

1\. The fact that they are raising money through indiegogo heavily implies
that they don't have a convincing plan to get their product at the promised
price point (which would very definitely sell if they did).

2\. They have 9 people on their team. I found the founders the graphic
designers and the communications experts but not the engineers.

I think this is just another case of "lets make a cool website about a product
that is very much in need, raise money, and then start thinking about how to
actually deliver".

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Pfhreak
Ok, I'm willing to believe you _could_ build a car that charges ~15m a day
from optimal sunlight exposure. Maybe.

But what I don't understand is how having a living moss interior attached to
your air supply is anything other than a terrible idea. There are so many edge
cases/issues I can imagine with trying to integrate a living component into a
car interior. (How does it handle extreme temperatures? How do you manage
moisture levels? What happens if it dies? How are you ensuring it remains pest
free?)

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onmobiletemp
This is a complete waste of time. Cells attached to the car will net you way
less energy than they claim (well they claim distance, i dont know if their
wh/km or wh from the panels is off, but one or both are). Panels on the car
could help prevent charge loss while parked for long periods or in extreme
cold but its less and less necessary as capacity steadily increases. The only
reason this might be useful is if you want to be a nomad amd never use
charging infrastructure. But youd get way more energy for way less money by
carrying panels in the trunk of your car or converting a large rv to solar and
carrying panels as well. As panels get cheaper we will see more cars with
solar but it will be small and for air con and stopping charge loss, not
range.

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sandworm101
For the price of integrating the panels into the car you could setup 10x as
many panels on a stationary rig. A portable folding rig kept in the trunk is
probably a better solution. It could at least be positioned for maximum
exposure without trying to angle the entire car. (I predict accidents as
people attempt to tilt these things.)

------
dimman
I must say I'm extremely sceptical as it would surprise me _a lot_ if they
managed to pull this off with a couple hundred k euros; meaning that they
produce something that 1) Actually works, 2) Is rather solid, and perhaps most
important of all 3) Is not a disaster in terms of safety.

------
Shivetya
Don't see it. Is there generation amount based on perfect conditions because
its quite possible the majority of the car would not have exposure all at
once.

------
whazor
A previous student team who won the solar race from the Netherlands is also
planning to go into the solar car industry.

