1. Order of Kilopi
Join Date
Oct 2006
Posts
3,767
Originally Posted by NEOWatcher
I'm just using numbers in units that the industry is providing. Whether they make total sense or not, doesn't mean that it's the most logical choice of "ballparking". Only that it's the best that I can find.

I would be glad to see things stated in real units (and related to kwh, which is what we pay for).
No - you've confused things. 34kw is a RATE of energy. 100 miles requires an AMMOUNT of energy. If 'industry' is providing these wrongly, please show us where.

Perhaps you means 24kWh? That's the amount of energy in the battery of a Leaf.

From http://en.wikipedia.org/wiki/Photovo...ion_and_energy we can see that the total ammount of solar energy in 1sqM in a day is about 4 - 6 kWh. Combine that with thefficiency of available solar panels ( http://en.wikipedia.org/wiki/Photovo...ule_efficiency ) and you get about 1kWh / sqM / day

You could fit perhaps 3sqM of solar arrays on the top of a LEAF. So 3kWh / day

At which rate it would take more than a week to charge a LEAF - or in one day you would generate enough power to travel about 8-10 miles. Less than a third the average distance driven by a LEAF owner per day.

2. Originally Posted by djellison
No - you've confused things.
I can accept that...
Perhaps in my haste, the "h" dropped of in the conversion to miles.

But the ballpark isn't that far off. We each started with some different data for the numbers, so naturally we have some differences in results. Your numbers do support what my point is even if mine were misleading.

3. Order of Kilopi
Join Date
Feb 2005
Posts
7,193
Well, if you want to wirelessly beam power from roof-to-car, perhaps that could be done without need for infrastructure on the roads. Electrical power could be handed off roof to roof as you drive. Cell-Tesla style.

Your car would charge itself--and if it drives itself and wrecks are eliminated, the car can be much lighter. The key is to combine appraches, and not work in isolation. It pays to be scatterbrained--a generalist.

Maybe cars don't need solar panels, but rectennas and clear lines of sight to the roof of the car to building emitter. Space based solar power solutions--in the hood.

4. Order of Kilopi
Join Date
Oct 2006
Posts
3,767
An electric car uses abotu 50kW on acceleration

Do you know what 50kW microwave transmitters look like? The dishes of the deep space network, that's what.

What a hideously dangerous, ludicrously expensive and utterly impractical idea.

5. Order of Kilopi
Join Date
Feb 2005
Posts
7,193
If not the roof then we are back to the roadbed again. Those will have to be resurfaced at some point of time anyway... I would think very lightweight cars would not have to have 50kW. I'm hoping there will be some kind of workaround that wouldn't be a strain on infrastructure.

6. Established Member
Join Date
Jul 2002
Posts
1,541
Originally Posted by publiusr
If not the roof then we are back to the roadbed again. Those will have to be resurfaced at some point of time anyway... I would think very lightweight cars would not have to have 50kW. I'm hoping there will be some kind of workaround that wouldn't be a strain on infrastructure.
you can add a power rail to the innermost lane on the highway and allow cars to have side-mounted pickups like some subway trains have. there are some safety issues with this however. one being that high voltage rails tend to be dangerous to accidentally touch. another option is to use the slot-car approach. altho i think the maintenance for that is goign to be a big issue.

7. Order of Kilopi
Join Date
Feb 2005
Posts
7,193
I'm just hoping that some workaround can be had to avoid cars having to have huge batteries. I don't know what that might be. Maybe there will be breakthroughs in terms of energy density for self powered cars.

8. Established Member
Join Date
Jul 2002
Posts
1,541
Originally Posted by publiusr
I'm just hoping that some workaround can be had to avoid cars having to have huge batteries. I don't know what that might be. Maybe there will be breakthroughs in terms of energy density for self powered cars.
Synthetic fuels can match the energy density of hydrocarbons. problem solved. Hybrid IC/electric cars are very efficient at their energy use. and they got the long range capability of a conventional IC powered vehicle as well.
The best way to store power for vehicles is as synfuels. synfuels can be made with CO2 and loads of energy. even just by using heat directly. there is absolutely no excuse for not building nuclear powered synfuel plants to fabricate all the vehicle fuel we need. it is also the easiest to convert too since it does not require everyone to get a new expensive vehicle, it can re-use existing fuel infrastructure, and best of all. it does not require people to do major changes to their lives in order to accommodate the new energy carrier. People are very protective of their lifestyles you know. they will resist any and all changes that threaten the way they do things today.

9. Established Member
Join Date
Dec 2009
Posts
255
Originally Posted by publiusr
I'm just hoping that some workaround can be had to avoid cars having to have huge batteries. I don't know what that might be. Maybe there will be breakthroughs in terms of energy density for self powered cars.
The batteries are not inherently huge, especially when you consider it as battery + electric motors + wires vs fuel tank + combustion engine + transmission + brakes. Even the electronic complexity is less compared to all the adjustments modern cars make to their fuel injection vs regenerative breaking.

I think battery electric is worth it simply for simplification of people's lifestyles. And no, an interchangeable battery system is not "complicated"... the entire electric car system is less complex than a quarter of a conventional car's system. This should allow for reduced manufacturing expenses, severely reduced maintenance requirements... LiPo is not going to be too large for this, especially if swappable.
Last edited by JCoyote; 2012-Jul-15 at 03:09 PM.

10. Established Member
Join Date
Jul 2011
Posts
265
Originally Posted by Antice
you can add a power rail to the innermost lane on the highway and allow cars to have side-mounted pickups like some subway trains have. there are some safety issues with this however. one being that high voltage rails tend to be dangerous to accidentally touch. another option is to use the slot-car approach. altho i think the maintenance for that is goign to be a big issue.
No need for rails: http://www.conductix.com/en/news/201...es-iptr-charge
The idea is as simple as it is clever: Inductive Power Transfer – or IPT – is an energy transfer system for electric vehicles that works by magnetic resonance coupling. The system consists of two main components: a primary coil, which is connected to the electricity grid via an infeed converter, and a pickup coil integrated in the floor of the bus. This technology permits an efficient, automatic, contactless transfer of energy...While charging, the current collectors on the bus take up a position about 40 mm from the charging coil in the ground, facilitating an extremely efficient energy transfer: 95% of the energy taken from the electricity grid is stored in the battery during normal operation...This allows the capacity of the batteries to be reduced by as much as 75%...there are about 30 electric buses in Genoa and Turin that have been using the company’s IPT technology since 2002

11. Originally Posted by Antice
Synthetic fuels can match the energy density of hydrocarbons. problem solved. Hybrid IC/electric cars are very efficient at their energy use. and they got the long range capability of a conventional IC powered vehicle as well.
The best way to store power for vehicles is as synfuels. synfuels can be made with CO2 and loads of energy. even just by using heat directly. there is absolutely no excuse for not building nuclear powered synfuel plants to fabricate all the vehicle fuel we need. it is also the easiest to convert too since it does not require everyone to get a new expensive vehicle, it can re-use existing fuel infrastructure, and best of all. it does not require people to do major changes to their lives in order to accommodate the new energy carrier. People are very protective of their lifestyles you know. they will resist any and all changes that threaten the way they do things today.
Not just match the energy density of hydrocarbons, they *are* hydrocarbons. And thus can feed into our existing chemical industry infrastructure as well as serving as a compact, convenient, and safe energy storage and transport medium.

12. Established Member
Join Date
May 2008
Posts
437
I think that batteries will get better and significantly cheaper in the next decade. But even with that I am extremely skeptical solar will be anything more than a small niche because of its fundemental limitations.

13. Established Member
Join Date
Jul 2002
Posts
1,541
Originally Posted by cjameshuff
Not just match the energy density of hydrocarbons, they *are* hydrocarbons. And thus can feed into our existing chemical industry infrastructure as well as serving as a compact, convenient, and safe energy storage and transport medium.
Shhhh. don't let the secret out. you may convert someone to start believing that the power of the atom may solve all our needs, not just the energy ones.

14. Originally Posted by djellison

At which rate it would take more than a week to charge a LEAF - or in one day you would generate enough power to travel about 8-10 miles. Less than a third the average distance driven by a LEAF owner per day.
That's it! I'll buy four more Leafs and equip them all with solar panels!

15. Originally Posted by Antice
you can add a power rail to the innermost lane on the highway and allow cars to have side-mounted pickups like some subway trains have. there are some safety issues with this however. one being that high voltage rails tend to be dangerous to accidentally touch. another option is to use the slot-car approach. altho i think the maintenance for that is goign to be a big issue.
In Vancouver WA, many of the left turn lanes park your car for up to three minutes: plenty of time for a quick coupling device to add a few blocks of juice...

16. Established Member
Join Date
May 2008
Posts
437
Originally Posted by Jerry
In Vancouver WA, many of the left turn lanes park your car for up to three minutes: plenty of time for a quick coupling device to add a few blocks of juice...

17. Established Member
Join Date
Jan 2010
Posts
470
Originally Posted by Van Rijn
Even with 100% efficient panels, the amount of energy would be pretty limited.
I'm not so sure the amount of energy would be to limited.
Solar Challenge cars must run entirely on solar energy, they drive 3000km in 50 hours. As i understand it they are completely self-sustained wrt energy.
http://www.worldsolarchallenge.org/

Obviously those cars are not commuter cars, but i think 100% efficient solar cells would go a long way toward making the technology suitable for common use.

18. Originally Posted by noncryptic
I'm not so sure the amount of energy would be to limited.
Solar Challenge cars must run entirely on solar energy, they drive 3000km in 50 hours. As i understand it they are completely self-sustained wrt energy.
You can also build a toy car that gets about 2000 miles per gallon. These aren't practical car designs. As I said before, forget crash protection, air conditioning, heating. A good wind will blow them over. Don't expect to drive them at night, cloudy winter day, etc.

Obviously those cars are not commuter cars, but i think 100% efficient solar cells would go a long way toward making the technology suitable for common use.
It wouldn't make enough of a difference to really matter, assuming it was possible. You're still going to have an impractical car. And why would you want to bother? You're going to need power storage anyway with a practical car, so it would make more sense to charge up from fixed panels, not on the car.

19. Established Member
Join Date
May 2008
Posts
437
Originally Posted by Van Rijn
You can also build a toy car that gets about 2000 miles per gallon. These aren't practical car designs. As I said before, forget crash protection, air conditioning, heating. A good wind will blow them over. Don't expect to drive them at night, cloudy winter day, etc.

It wouldn't make enough of a difference to really matter, assuming it was possible. You're still going to have an impractical car. And why would you want to bother? You're going to need power storage anyway with a practical car, so it would make more sense to charge up from fixed panels, not on the car.

But here's the thing, unless you're in a remote location that's off the grid why would you want to use panels in the first place?

20. Established Member
Join Date
Jun 2010
Posts
652
Originally Posted by Jerry
That's it! I'll buy four more Leafs and equip them all with solar panels!
Good thinking Jerry. You can lash them together in a train and when the towing car runs out of battery switch it to the back and keep going. Hmmm, could be a flaw there somewhere.

The Leaf got a very bad review in The Australian. The money quote
Every way you turn with the Leaf, there's a killer disadvantage.

21. Order of Kilopi
Join Date
Oct 2006
Posts
3,767
Originally Posted by noncryptic
but i think 100% efficient solar cells
Where do you buy 100% efficient solar cells from?

You know how efficient solar cells are at the moment, right?

22. Established Member
Join Date
Sep 2005
Posts
1,515
Originally Posted by aquitaine
Do you realize how many amps/hour have to be transmitted to recharge a car battery?
Wireless is not a direct connection from device to device.
There are a LOT of losses in wireless power, too.

And you have people screaming now about health effects from 2.4ghz routers pumping out a watt,
can you imagine how they'll scream if car owners put up 20,000watt wireless chargers???

23. Aren't solar cells currently running about 40% efficiency? I wouldn't expect great gains on that; and the power available varies greatly with latitude. In Portland, I suspect there are at least two good days per month...in the Summer.

24. Established Member
Join Date
Jul 2002
Posts
1,541
Originally Posted by JustAFriend
Do you realize how many amps/hour have to be transmitted to recharge a car battery?
Wireless is not a direct connection from device to device.
There are a LOT of losses in wireless power, too.

And you have people screaming now about health effects from 2.4ghz routers pumping out a watt,
can you imagine how they'll scream if car owners put up 20,000watt wireless chargers???
if you output 20Kw at 2,4GHz then i don't wanna be anywhere near that sucker either. That is a LOT of power being transmitted. Sometimes the screaming does have a good justification.

25. Originally Posted by Jerry
Aren't solar cells currently running about 40% efficiency? I wouldn't expect great gains on that...
Are you looking at best or average performance, and what sort of average?

26. If we get to sufficient numbers of electric vehicles , we may perhaps see electric charging stations at our work parking lots. Where that electricity comes from is a separate question. Clearly....charging your battery at 440 volts is more practical and more efficient.

Best regards,
Dan

27. Established Member
Join Date
May 2008
Posts
437
Originally Posted by Jerry
Aren't solar cells currently running about 40% efficiency? I wouldn't expect great gains on that; and the power available varies greatly with latitude. In Portland, I suspect there are at least two good days per month...in the Summer.
According to the wiki that's the state of the art in the lab. But even so, 40% of 1 kw/m^2 isn't really that much......

28. Order of Kilopi
Join Date
Oct 2006
Posts
3,767
Originally Posted by Antice
if you output 20Kw at 2,4GHz then i don't wanna be anywhere near that sucker either. That is a LOT of power being transmitted. Sometimes the screaming does have a good justification.
It's comparable to the output of the 34m antennae of the deep space network. They notify the FAA of their schedule so that airplanes don't fly thru the radiated power, 30,000ft above.

Puts it in context.

29. Established Member
Join Date
Jul 2002
Posts
1,541
Originally Posted by djellison
It's comparable to the output of the 34m antennae of the deep space network. They notify the FAA of their schedule so that airplanes don't fly thru the radiated power, 30,000ft above.

Puts it in context.
it has to be focused within a receiver. on say, the underside of the car. the density of this beam would have to be much higher the one from the DSN. much higher in fact. than the power density inside a microwave.

30. Established Member
Join Date
Jul 2011
Posts
265
Originally Posted by Antice
it has to be focused within a receiver. on say, the underside of the car. the density of this beam would have to be much higher the one from the DSN. much higher in fact. than the power density inside a microwave.
Aside from the link in post #40 indicating the Conductix-Wampfler solution, Toyota has also invested in a wireless charging solution with WiTricity (MIT spinoff), which is also part of the Delphi solution: http://gigaom.com/cleantech/toyota-t...-car-charging/. Then there's the Qualcomm Halo solution (http://www.qualcommhalo.com/) for wireless charging. They all use basically the same technology (magnetic resonance) to quickly and safely recharge electric vechicles. As the blurb on the Qualcomm site notes: "The Future is Wireless EV Charging"

Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•