Author Topic: Debunk suggestion: Solar car  (Read 1359 times)

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Offline lvictorlucas

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Online digsys

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Re: Debunk suggestion: Solar car
« Reply #1 on: July 07, 2017, 11:29:17 pm »
Quote from: lvictorlucas
This one should be easy ...
I hope you're not serious !
I've been involved with solar cars for ~ 15yrs, our club nearly 30 yrs. Our race cars are capable of over 900Km a day, approx 50/50 battery / solar.
And that is only a 22Kg pack @ 5KWh. A few years ago, after 25yrs of design improvements, we decided to start a new class - road legal vehicles (or capable of), 2-4 person.
Each year more and more teams are submitting entries, and they are getting better and better. Extensive testing and modelling tells us that we should be able
to achieve ~250-250Km solar and 200-250Km battery (on a 25KWh pack). Note: we have been doing this for quite a while, and there are dozens of universities around the
world putting a LOT of research into it. It will happen soon enough !!
CAVEATS !! Yes, the cars are extremely light and aerodynamic shaped, which means they WON'T be ANYTHING like the Teslas of the world. This stupid obsession with faster
and more powerful than anyone else has to be addressed. With all that is going on, it is beyond belief how far this obsession is pushed.
YES, there have been a few production solar cars over the last few years. Yes, they are quite limited in range and power, and one or two were pretty impractical, but
it IS A START in the right direction IMO !
Bottom line, you may find all this laughable, but LUCKILY, you don't run the planet !

Edit: btw, Welcome to EEVBlog
« Last Edit: July 07, 2017, 11:32:18 pm by digsys »
Hello <tap> <tap> .. is this thing on?
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Offline TacticalCode

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Re: Debunk suggestion: Solar car
« Reply #2 on: August 08, 2017, 12:21:21 am »
I think the concept of a "Solar Car" will work in the near future.

Sure, you get fantastic results with cars designed for achieving unrealistic results. But I don't think we can affordably put together a car that can do at least 80Km/h, transport 3-4 people (avg Family), and still be stable enough to protect passengers in case of a crash.
That, and aerodynamics are a huge challenge. You're essentially designing a sail - as much surface area as possible as lightweight as possible. Show me a design that fits on normal roads and offers similar comfort in entering/exiting the vehicle as a normal one.
As far as I understood, weight plays the major role in solar cars, because more mass means more energy is consumed to achieve a set velocity.
To compensate, more battery capacity is needed, which means more mass, and so on. The solar cars I've seen so far were rather fragile to skimp on weight, or made from too expensive materials.

And then again, solar strikes. What if I need to drive at night, when there is no sun? In the winter, when snow and ice cover all panels? Then your fancy solar car is just a normal electric vehicle, which takes a buttload of time to charge. Gasoline just works(tm). Pour it in, away you go.

I'm all for solar and reducing greenhouse effect, but solar cars won't be practical for a long time, in the sense that ALL of the electricity comes from solar panels on your car itself, providing a comparable experience/comfort to regular vehicles. Of course, feel free to mount solar panels on your car to increase your mileage, be more independet, etc. But you just can't rely on the technology yet.

I think we need to get normal Electric Vehicles right first, then we can talk about efficiency or even trying to become autonomous to external power. What we really need, is a safe and quick way to charge normal solar vehicles. And by quick I mean no longer than filling up your gas tank takes. Which we currently can only do safely by swapping out the battery. Problem is, every car manufacturer will have their own battery design, so there's no incentive to agree on a common form factor and placement, to make it compatible to automated battery exchangers, which could "charge" your Electric Vehicle even faster than filling your tank. Any of you guys remember your old phone charger? Do you know why today, you can simply plug in your USB cable to any phone there is? (Unless it's an Apple Toy or has USB-C, which will phase out µUSB shortly...) That's right, the EU has ordered all manufacturers to agree on a common standard for everybody to use, just because there was so much unnecessary waste generated due to people throwing their old chargers away when they got a new phone with a different charger. Manufacturers would have kept doing this, they will of course gain money by selling more/newer chargers.

To come back to the topic of EVs... If the batteries in your solar car run flat at night, you're screwed. There's nothing you can do about it, the next best thing to get going again is a conventional battery charger. If you can't afford to spend the entire time waiting for your battery to charge up, you're still screwed! The only winner, currently, is combustable dinosaurs. If your gasoline car runs flat at night, in the middle of the desert, you can pop out a can of gas, pour it in, and be going again in under 5 minutes. Maybe there will be a vehicle to transport people just using its own solar power in 10 or 20 years... But that vehicle won't be a car. Cars are the most inefficient way of transport, and people got used to that convenience. I do fully expect charging times go down though, and once people can charge their desired range in under 10 minutes, let's say you can add 100km range in 10min, that's when the majority of people will switch over to electric.

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