Teslas use approx. 300-500 Watts of power to run house loads (computers, coolant pumps, fans, DC/DC converters and so on) while charging. The roof of a modern car is only in the order of 10 square feet of flat surface, maybe a little more, but soon you are hitting the windshield, back window or the side rails. That 10 sq ft (1 sq meter) gives you about 1000W of irradiation (energy from the sun) when straight above. Good solar panels can convert this into approx. 150 Watts of power if there is no shadowing, no dirt, no heat and when the sun is directly overhead. So, even under ideal circumstances a roof mount solar panel would not be able to run the parasitic loads of a typical EV, so it would *discharge* the main pack when enabling solar charging. I have a similar thing with a USB power bank that some Chinese designer slapped a solar panel onto and in order to control the charging, it enables the processor and blinking LEDs to show how much it is charged, plus the DC/DC converter that is used to convert 3.x Volts from the cell to power the USB outputs. Result is that under ideal circumstances, half the power is used in parasitic loads, the other half can charge the bank’s cell. However, if the circumstances are not ideal and it is just seeing ambient light, then there is almost no power from the solar panel. But it has enough voltage to turn on the processor. So, after a couple hours of indirect daylight on the solar panel, the bank is fully *dis*charged. I plan on rewiring the solar panel directly to the cell and not enable the processor and DC/DC converter unless using the USB output. That way it can opportunity charge without running down. Cor.
Sent from Mail for Windows 10 From: Larry Gales via EV Sent: Sunday, December 9, 2018 12:00 AM To: Electric Vehicle Discussion List Cc: Larry Gales Subject: Re: [EVDL] EVLN: Musk walked-back on PV roof option> too small asurface Why has no one mentioned the obvious: the Stella Lux and Stella Vie which achieve practical solar power because they are extremely lightweight and sport a 1.2 to 1.5 solar PV. The Dutch team that has produced these street legal vehicles (4-5 passengers, top speed of 77 mph) is also working on a production model named "LightYear" On Sat, Dec 8, 2018 at 9:40 PM paul dove via EV <ev@lists.evdl.org> wrote: > (Eight hours of charging Tesla’s Model 3 from a wall socket will > give you your expected 200-plus miles of range.) > Someone's math is off. You can only get 1KW/h from a wall socket. Maybe 30 > miles in 8 hours. > > On Saturday, December 8, 2018, 8:05:15 PM CST, brucedp5 via EV < > ev@lists.evdl.org> wrote: > > > > https://qz.com/1482588/why-teslas-dont-and-cant-have-solar-roofs/ > Why Teslas don’t—and can’t—have solar roofs > December 3, 2018 Kabir Chibber > > [images > https://cms.qz.com/wp-content/uploads/2018/12/RTX1A0WZ.jpg > The only solar-powered cars that work > > https://cms.qz.com/wp-content/uploads/2018/12/RTS1WEN8.jpg > The Sono prototype / REUTERS/Andreas Gebert > ] > > It’s a pretty intuitive question. “Why don’t electric cars have solar > roof[s?]” asked one person in the “No Stupid Questions” area of Reddit. > “Wouldn’t it make sense to have a self sustaining charging capabilities.” > There are similar questions on Quora and elsewhere. > > Teslas and other cars run off electricity, drawing from an electric-power > infrastructure that often runs off of dirty fuels. Solar power generates > lots of electricity for free from the sun. Why don’t electric cars have > solar roofs to power them for free? > > For one thing, the math makes it quite difficult. Elon Musk briefly > suggested that solar roofs would be an option for the Tesla Model 3, but > later walked it back and explained why. “Putting solar panels on the car > itself?” Musk said in July 2017. “Not that helpful, because the actual > surface of the car is not that much, and cars are often inside. The least > efficient place to put solar is on the car.” It turns out that he had meant > a solar roof that unfolds from the trunk and overs the current car hood. > > A Tesla rival, the Karma Revero, actually has a solar roof as an option. As > Wired noted (paywall), modern solar panels are inefficient and convert just > 15-20% of the energy that reaches them. So that Revero solar roof, having > received eight hours of pure sunshine, will generate enough power to drive > 1.5 miles. (Eight hours of charging Tesla’s Model 3 from a wall socket will > give you your expected 200-plus miles of range.) > > On Quora, Chris Harget, a product-marketing manager in the Bay Area, > summarizes the problems (emphasis added by him): > > The top of an electric car has maybe 3–5 square meters of flat space. > > Solar panels, even at high noon, usually only produce about 200 > watt-hours per square meter. > > The most efficient production electric vehicles today (probably the > Hyundai Ioniq and the Tesla Mod 3) would only be able to travel 2–4 miles > on > that amount of electricity…in an hour. Most people could walk faster. > > Financially, the cost of the panels and electronics, R&D and assembly > would never pay for itself in the life of the vehicle, compared to charging > from the wall in your garage. > > That doesn’t mean no one is trying. There’s a German startup called Sono > Motors that wants to build cars with solar panels. Toyota last year > announced that upcoming Prius hybrid cars would come with Panasonic solar > roofs (paywall). > > Still, even as solar panels become more common and more efficient, they > won’t be on most cars anytime soon. > [© qz.com] > > > + > > https://www.businessgreen.com/bg/news/3067447/vattenfall-begins-rollout-of-wind-powered-ev-chargers-in-norfolk > Vattenfall begins rollout of wind-powered EV chargers > 04 December 2018 Vattenfall is set to begin rolling out its first UK > electric vehicle (EV) chargers in Norfolk this week, after today announcing > a new partnership with BMM Energy ... > > https://www.businessgreen.com/w-images/0e05a981-078a-438e-a16e-cca8813b0f5f/3/InchargeatPyC-580x358.jpg > > > > > For EVLN EV-newswire posts use: > http://evdl.org/archive/ > > > {brucedp.neocities.org} > > -- > Sent from: http://electric-vehicle-discussion-list.413529.n4.nabble.com/ > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Please discuss EV drag racing at NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20181209/5e5718ed/attachment.html > > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Please discuss EV drag racing at NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -- Larry Gales -------------- next part -------------- An HTML attachment was scrubbed... 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