Mobile Solar Charging

[TomT]

The Leaf has a length of 4445mm, and a width of 1770mm. This is about 7,867,650mm^2 = 7.868sqm, or ~84sqft.
I guess you missed the part where I said "with the correct angle of incidence..." Most of that will be either be in shade or at such a steep angle to the sun as to have extremely poor efficiency... I suspect that the effective usable area is something less than 1/3 of that.

Soitec achieved 44.7% efficiency in Sep 2013
And is entirely vaporware at this point. Just over 20% is the best efficiency of panels currently available in the wide market... Even at 40% it would be a terrible ROI in this application for the above reason.

 

[mctom987]

I guess you missed the part where I said "with the correct angle of incidence..." Most of that will be either be in shade or at such a steep angle to the sun as to have extremely poor efficiency... I suspect that the effective usable area is something less than 1/3 of that.

Because raising one side 1' is impossible…

 

[TomT]

You need to roughly equal the latitude of your location in elevation for maximum efficiency. And this doesn't even consider the fore and aft pitch of the hood (which is included in your square foot calculation)... One foot won't do either. But go for it and do let us know how it turns out.

I guess you missed the part where I said "with the correct angle of incidence..." Most of that will be either be in shade or at such a steep angle to the sun as to have extremely poor efficiency... I suspect that the effective usable area is something less than 1/3 of that.

Because raising one side 1' is impossible…

 

[DougWantsALeaf]

I am loving the responses. Roi never really entered the equation.

You can buy space grade panels which get you into the 30s.

Also, we can't cover the windshield.

But agreed, with a custom set up, you might get close to 5 miles of range an hour at midday.

 

[mctom987]

And this doesn't even consider the fore and aft pitch of the hood (which is included in your square foot calculation)... One foot won't do either. But go for it and do let us know how it turns out.

Because there's no need to. Put it above the car. Unless you were referring to a solar absorbing paint that has yet to be made?
Raising the side 1 foot would give you a 10° slope. Certainly not perfect for everywhere, but just raise it more or less, depending on your latitude.

Edit: Not a great example, but placing the panels something like this:

 

[kikngas]

Great project. I applaud your efforts. In the spirit of thinking outside of a different box, let me attempt to crystallize some of the apparent issues so far:

• Need larger panel area to get meaningful charge

• Optimize angle of incidence to make most of available panel area

• Ideal to avoid impact on vehicle aerodynamics

• And the usual, make it cheap, make it durable...

Picturing the solar sun racers, they extend the dimensions of the vehicle to get more panels on.

So, in the spirit of changing the rules to help assure a win, have you considered changing your expectations? My understanding of the current idea is that you plan to charge while parked and while driving, and this imposes some limitations (such as not being able to use the area of the windshield for PV, the need to withstand wind force at driving speed etc.). What if your plan was to drive somewhere, then charge while you are there, and then drive back?

In that light, I had this idea a couple of weeks ago while considering how one might use the cheap broken 4x6" solar cells that you can get on EBay. The cells are not mounted in a panel and so you are more flexible on overall shape, but now you must somehow protect the cells from further breakage. So I half-baked something like this:

String the cells together and stack them, picture a Venetian blind. This collapses and can stack into a box for transport, without taking up all of the trunk. Add some framing and a flip out leg (like an easel stand), and the whole thing stands on the ground. Offset the holes in the cells from center so they expose their surface when extended, and such that a wind blows the cells open and flows between them. You briefly lose proper incidence, but your easel doesn't blow over (fingers crossed). Perhaps the whole easel can yield vertical axis to the wind as well or you can design a deflector that allows the extended panel to stay facing the sun, or you can anchor them to the car in some way (thus shading it and avoiding high heat on battery). You make several of these "panels".

This gives you as much surface area as you care to store and assemble. It allows you to track to the sun if desired rather than fix mounted to the car. The whole kit is stored within the car without modification to the car, so no impact on aerodynamics.

 

[foolios]

Neat!

I wonder if carrying around a wind turbine instead or in combination would work?
So you're cruising down the road and the wind caught by the turbine gets turned back into energy.
Maybe more power than a panel?
Why wouldn't that be possible?

 

[TomT]

I think your name says it all... You have just invented the vaunted perpetual motion machine!

So you're cruising down the road and the wind caught by the turbine gets turned back into energy.
Maybe more power than a panel? Why wouldn't that be possible?

 

[foolios]

Here's this conversation in practice.

AWESOME!!!!

http://gas2.org/2014/12/03/record-setting-sunswift-solar-car-turns-to-crowdfunding/

 

[mikesus]

I think you are going about this wrong.


The only meaningful way to have any effect on range would be to use a large battery.

(this was done by Solectria back in the 90's by putting them on a trailer. It had a cute turtle cover on it but I digress)

Racking 5 300w panels would get you 1350w in full sunlight. You could add more losses by trying to convert this to back to AC, but you would do a LOT better to think CHAdeMO.

https://www.youtube.com/watch?v=o-Oosm3yjWM" onclick="window.open(this.href);return false;

 

[theleafer]

Great project. I applaud your efforts. In the spirit of thinking outside of a different box, let me attempt to crystallize some of the apparent issues so far:

• Need larger panel area to get meaningful charge

• Optimize angle of incidence to make most of available panel area

• Ideal to avoid impact on vehicle aerodynamics

• And the usual, make it cheap, make it durable...

Picturing the solar sun racers, they extend the dimensions of the vehicle to get more panels on.

So, in the spirit of changing the rules to help assure a win, have you considered changing your expectations? My understanding of the current idea is that you plan to charge while parked and while driving, and this imposes some limitations (such as not being able to use the area of the windshield for PV, the need to withstand wind force at driving speed etc.). What if your plan was to drive somewhere, then charge while you are there, and then drive back?

In that light, I had this idea a couple of weeks ago while considering how one might use the cheap broken 4x6" solar cells that you can get on EBay. The cells are not mounted in a panel and so you are more flexible on overall shape, but now you must somehow protect the cells from further breakage. So I half-baked something like this:

String the cells together and stack them, picture a Venetian blind. This collapses and can stack into a box for transport, without taking up all of the trunk. Add some framing and a flip out leg (like an easel stand), and the whole thing stands on the ground. Offset the holes in the cells from center so they expose their surface when extended, and such that a wind blows the cells open and flows between them. You briefly lose proper incidence, but your easel doesn't blow over (fingers crossed). Perhaps the whole easel can yield vertical axis to the wind as well or you can design a deflector that allows the extended panel to stay facing the sun, or you can anchor them to the car in some way (thus shading it and avoiding high heat on battery). You make several of these "panels".

This gives you as much surface area as you care to store and assemble. It allows you to track to the sun if desired rather than fix mounted to the car. The whole kit is stored within the car without modification to the car, so no impact on aerodynamics.

Thank you,

All of the limitations came together and were against me on this one. I looked at the flexible panels. They were ideal because the drag would be very low, if even enough to take into account. The issue was that they were a lot more expensive and the output was so much less than a standard panel. I thought about removing the aluminum frame for the panel but seeing that it was going to be used for other things after my project was over I decided against dismantling the frame.

 

[KillaWhat]

Neat!

I wonder if carrying around a wind turbine instead or in combination would work?
So you're cruising down the road and the wind caught by the turbine gets turned back into energy.
Maybe more power than a panel?
Why wouldn't that be possible?

So..... Not an engineer , eh?

 

[dsny]

Neat!

I wonder if carrying around a wind turbine instead or in combination would work?
So you're cruising down the road and the wind caught by the turbine gets turned back into energy.
Maybe more power than a panel?
Why wouldn't that be possible?

So..... Not an engineer , eh?

Speaking of wind power and autos... Of course a fan on the roof causes drag. But is there any fan that could lock if any drag force were present but be capable of unlocking when it determines that it would create no drag? Something like a very intelligent sail boat...

On another topic... How would using fans for regenerative braking compare to using the AC motor? If solar is on top of the car then fans or one large fan could go on the bottom or sides. Maybe a material that is made up of many small fans?

:idea: How about a big spring that you leave out behind your car at stop lights that other cars push into to slow down, and which in turn charges your battery? Too bad for them for not having regenerative braking. But it is a win-win, saving their brake wear and all.

(Of course a wiser way to save energy right now would be to automate traffic just enough to greatly reduce the need to ever apply the brakes. Even until reaching your final destination.)

Actually this last - the spring - could go in immediately at many, many modern intersections. Consider it like a DC charger station, the EVs parked on the sides of the road. Again, this only works as long as there are ICEs on the road...but there are plenty now so it is okay. Just one set of cars stopping at a light could provide a lot of equivalent regenerative braking.

 

[GetOffYourGas]

Neat!

I wonder if carrying around a wind turbine instead or in combination would work?
So you're cruising down the road and the wind caught by the turbine gets turned back into energy.
Maybe more power than a panel?
Why wouldn't that be possible?

So..... Not an engineer , eh?

Speaking of wind power and autos... Of course a fan on the roof causes drag. But is there any fan that could lock if any drag force were present but be capable of unlocking when it determines that it would create no drag? Something like a very intelligent sail boat...

On another topic... How would using fans for regenerative braking compare to using the AC motor? If solar is on top of the car then fans or one large fan could go on the bottom or sides. Maybe a material that is made up of many small fans?

:idea: How about a big spring that you leave out behind your car at stop lights that other cars push into to slow down, and which in turn charges your battery? Too bad for them for not having regenerative braking. But it is a win-win, saving their brake wear and all.

(Of course a wiser way to save energy right now would be to automate traffic just enough to reduce the need to every apply the brakes. Even until reaching your final destination.)

Actually this last - the spring - could go in immediately at many, many modern intersections. Consider it like a DC charger station, the EVs parked on the sides of the road. Again, this only works as long as there are ICEs on the road...but there are plenty now so it is okay. Just one set of cars stopping at a light could provide a lot of equivalent regenerative braking.

I love the spring! I certainly can't see anything going wrong once those ICE cars come to a stop (like being propelled in reverse into the car behind them!). I think you should set up a kickstarter for road springs!

 

[dsny]

I love the spring! I certainly can't see anything going wrong once those ICE cars come to a stop (like being propelled in reverse into the car behind them!). I think you should set up a kickstarter for road springs!

Lol :lol:

 

[BrockWI]

My idea is to have LED lights that "move" down the road and you car locks in to that motion or location and it paces the cars so they can pass through every intersection without stopping, basically cars missing each other by a few feet as they pass one in front of the other. Its all about timing

The same thing could happen on freeways. If everyone is going 10mph, the system could just speed everyone up to 60 mph with the same distance between them all. Seems safe right

 

[smkettner]

My idea is to have LED lights that "move" down the road and you car locks in to that motion or location and it paces the cars so they can pass through every intersection without stopping, basically cars missing each other by a few feet as they pass one in front of the other. Its all about timing

The same thing could happen on freeways. If everyone is going 10mph, the system could just speed everyone up to 60 mph with the same distance between them all. Seems safe right

Just put some trolley poles up on the roof.....

http://www.thebolditalic.com/articles/4717-hacked-prius-running-on-muni-power-lines

Long range EV becomes a non-issue

 

[Smidge204]

Just put some trolley poles up on the roof.....

The Super Mario Bros. movie did it first :lol:
=Smidge=