Even conventional solar PV cells on current EV designs can provide useful
range extension improvements. It doesn't need to cover 100% of demands to
be useful.

Range improvements are useful, as is neutralizing of vampire load losses,
or providing enough energy for limited cooling (some Priuses do this via
ventilation fans with their solar panels). Tesla's Raven refresh focused
on  increasing the efficiency of their drivetrain, not about increased
battery capacity. Tesla could reduce energy requirements further via heat
pump HVAC and vehicle roof/hood solar PV.

A Chevy Bolt has 5.19 m^2 of hood and roof area*. Using Maxeon cells with
22.6% conversion efficiency, that is 1.173 kW DC, before derating for
losses. Assuming 1/2 lost to fitment, soiling, orientation, and DC-DC
conversion, we still have >500 W. At 4.5 sun hours per day, we may collect
2.5 kWh. 2.5 kWh is 10 miles range on a small 250 Wh/mile EV. Covering
doors could further increase energy collection opportunities.

Is an additional 10 miles daily range useful or significant? It can be. If
the average driver goes 40 miles per day, 10 miles is 25% of their needs.
>From another perspective, Toyota's first Prius Plug-in models only had
about 10 miles all-electric range.

The owners it would benefit most are those who can park or use their
vehicles outside during the day. From a convenience perspective, apartment
dwellers with open parking lots, and without charging at their spaces,
would also benefit as being able to stretch their visits between chargers.
Camping would also benefit.

Such a system could provide 10 miles each day via onboard PV, with
additional miles from externally provided sources. 100% on 10 mile days.
25% on 40 mile days. 3% on 300 mile days.

Hyundai has a Sonata Hybrid model that uses this same concept:

https://cleantechnica.com/2019/07/22/the-solar-roof-on-hyundais-new-sonata-hybrid-adds-1300km-of-range-per-year/


*
https://www.artstation-vehicletemplates.com/images/WrapDimensionsSample.pdf



On Thu, Aug 22, 2019, 11:04 Matthew Pitts via EV <ev@lists.evdl.org> wrote:

> David,
>
> I agree that solar only vehicles don't make sense. But, solar assisted BEV
> "hybrids" that can charge from either the solar panels on the vehicle while
> in use or another source at night might be something to pursue.
>
> Matthew Pitts
>
> On August 22, 2019 11:56:00 AM EDT, EVDL Administrator via EV <
> ev@lists.evdl.org> wrote:
> >On 22 Aug 2019 at 13:12, Lawrence Rhodes via EV wrote:
> >
> >> The surface area for 3 kw of Sunpower Maxeon cells would be 8 feet by
> >23
> >>  feet.
> >
> >You're talking about a vehicle 15% longer and 31% wider than the
> >largest,
> >most bloated Chevrolet Silverado pickup.  That's a 37% larger
> >footprint.
> >Where are you going to park it?
> >
> >This allegedly "green" solar vehicle would take up 157% more road and
> >parking space than a VW Polo, and at least 900% more than a bicycle.
> >Where
> >on earth does that kind of personal vehicle make sense?
> >
> >What's more, it won't work.  Those 3kW PVs won't produce 3kW
> >continuously.
> >Vehicles travel and park in shade, on cloudy days, in winter, at night,
> >in
> >garages.  Do you want to be the one to tell Joe and Jane Suburbanite
> >that
> >they can't use their $50,000 garage to protect their $150,000 solar EV?
> >
> >At the current state of the art, I just can't see standalone solar
> >vehicles
> >as practical.  Maybe they'll be marginally practical someday IF we see
> >an
> >order of magnitude improvement in PV conversion efficiency, and IF that
> >
> >miraculous new invention is made from some cheap and plentiful material
> >in a
> >minimal-labor process requiring almost no energy input.  But I don't
> >see
> >that happening in my lifetime.
> >
> >Besides, I just don't get why the idea of a standalone solar vehicle is
> >so
> >compelling.  You have to sleep, so put your  PV on your house.  Right
> >now
> >that house is probably just sitting in the sun all day, converting the
> >sunlight to heat that you're pumping out with an air conditioner.  Why
> >not
> >capture that solar energy instead, save it with whatever method works
> >for
> >you, and pump it into your EV while you sleep?
> >
> >That kind of solar vehicle is simple, practical, efficient, and
> >relatively
> >affordable.  So why are we burning through person-hours developing
> >standalone solar vehicles that will never be affordable to anyone but
> >the
> >top 0.1% income range, and have zero chance of ever seeing commercial
> >production?
> >
> >You may have your own ideas, but I'll tell you what I think is one big
> >reason.  Standalone solar vehicles are sexy.  They snag the imagination
> >of
> >politicians and rich philanthropists with limited science education.
> >That
> >makes them a fabulous way to harvest grant money for both dodgy
> >"entrepreneurs" and legitimate but desperately underfunded nonprofits.
> >
> >David Roden - Akron, Ohio, USA
> >EVDL Administrator
> >
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> >EVDL Information: http://www.evdl.org/help/
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> >email address from the webpage http://www.evdl.org/help/ .
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> >
> >
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> --
> Sent from my Android device with K-9 Mail. Please excuse my brevity.
> _______________________________________________
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