# Impossible Dream? Coast to Coast In a Solar VW Bug



## Sunking (Aug 10, 2009)

Physics is going to bite you in the butt hard. Your first mistake is using battery solar panels.They are twice the cost of grid tied panels and low voltage at 18 Vmp. Much better off using GT panels wired in series for Vmp of around 100 volts and use a MPPT controller to charge with. 

Second challenge is one you cannot work around. So with 6 140 watt solar panels installed on a vehicle is not going to generate much power in a day. First they are not oriented or tilted correctly to get ample power. So instead of getting say a 4 Sun Hour Day this time of year you might get 3 Sun Hours if you are lucky. With a MPPT setup charge efficiency is as good as it gets 70%. So with 3 Sun Hours x 840 watts x .7 efficiency you will generate roughly 1.7 Kwh on a really good day. 

So how many miles is that on your vehicle in a day? . Well if you could achieve say 400 wh/mile efficiency gets you 4 miles in a day. 

Good luck that will be a very long trip. At 3 to 4 miles a day, you should be able to get across the country in about 4 years. You could walk 10 times faster than that. 

Good luck.

Sunking


----------



## evmetro (Apr 9, 2012)

I would get rid of the lead and go with lithium to save a lot of weight. You would want to size that lithium pack pretty small to save weight as well, since your range would only be a few miles per day.


----------



## Duncan (Dec 8, 2008)

If you want to (need to) do more miles/day
I suggest getting more panels and parking during daylight hours with your panels folded out and correctly aligned 
Then fold them up and stow them in/on the car and drive at night


----------



## onegreenev (May 18, 2012)

Can't fit 32 lead acid batteries in a BUG. I had one hell of a time squeezing in 16 in my Ghia. If you could shoehorn them in the weight would kill the car. You'd be looking at 2176 lbs of lead to haul around. Speed would be next to impossible to attain with an AC 15 in the bug. 

To go across the country why not do it but take with you your own generator for charging along the way. Use a diesel engine to power the generator so you can use veggie oil or bio diesel when you need to charge in places you have no way to charge. Also go with lithium batteries. 

If you want to do a trip across the country get a VW bus Single Cab and load the cargo bay with a fold out array of solar panels so you can pull them out when you need to charge. They will be excess weight but it would be easier to do and get an AC 35 or higher. Don't bother with any that are smaller. Be prepared to spend nights alone along the way. 

You will need a decent budget to pull this off. Check my blog for my ideas on generators to use for charging along a long trip. 

Pete 

It is possible that way but the solar is going to be much slower. Cost no matter which way you go will be pretty high.


----------



## SunBug (Sep 12, 2014)

Thanks for the advice, its a real challenge..

Drive only at night and fold the panels out and manually align them all day

GT Panels in series with a MPPT charge controller, thats some advice I can use.

...Got it.

The rest is gonna be tricky..

As for bringing a generator, that falls under cheating in this scenario and then its no longer the SunBug.

The Bug can only be propelled by sunlight gathered along the way. 

Thanks again everyone, keep the advice coming. Should I not use a AC motor?


----------



## Karter2 (Nov 17, 2011)

You are trying to do what the "Solar Challenge" teams do in Australia... drive across country using only solar charging/battery electric drive.
It can be done, but you wont do it in a bug with Lead batteries !
Google the solar challenge and you will see they have very special , custom built vehicles, very light with low aero resistance , small efficient motors and batteries, and large efficient solar surface panels.
Oh, and by the way, running those golf kart batteries into the ground WILL kill them pretty quick !


----------



## Duncan (Dec 8, 2008)

The batteries are a bit of a red herring
The amount of energy that you are dealing with is quite small - even if you use a set of folding panels you will be struggling to get more than about three Kw of panels,
That could give you 12 KiloWattHours of energy
So you would only need a 15Kwhr battery pack (to get 80% usage) - There is simply no point in having more batteries than you can charge


----------



## SunBug (Sep 12, 2014)

Duncan said:


> The batteries are a bit of a red herring
> The amount of energy that you are dealing with is quite small - even if you use a set of folding panels you will be struggling to get more than about three Kw of panels,
> That could give you 12 KiloWattHours of energy
> So you would only need a 15Kwhr battery pack (to get 80% usage) - There is simply no point in having more batteries than you can charge


Theres some advice I can use, save a lot of weight, which is a real enemy here


----------



## SunBug (Sep 12, 2014)

Karter2 said:


> You are trying to do what the "Solar Challenge" teams do in Australia... drive across country using only solar charging/battery electric drive.
> It can be done, but you wont do it in a bug with Lead batteries !
> Google the solar challenge and you will see they have very special , custom built vehicles, very light with low aero resistance , small efficient motors and batteries, and large efficient solar surface panels.
> Oh, and by the way, running those golf kart batteries into the ground WILL kill them pretty quick !


I have seen plenty of purpose built clean sheet of paper solar vehicles, but to do this with a street legalbug that has the aerodynamic coefficient of a billboard will be super tricky !! But thats all part of the SunBug challenge, which is basically impossible without crowdsourced intelligence, which is what I am doing, I definitely appreciate all the feedback from high ranking administrators here, thats a feelgood thing, my humble thanks..


----------



## Duncan (Dec 8, 2008)

Hi Scott
You won't have a lot of energy - BUT it takes less energy to go slowly - aerodynamics also becomes much much less important

If you have the 12Kwhrs each day
That will only take you 12,000/300watts/mile = 40 miles at about 40mph
But you have all day to do it 

By dropping to less than 20mph you will increase the distance traveled - probably nearly double

There are other advantages less power required - smaller motor - lighter - all helping your distance traveled

I think getting 60 miles/day is doable - is it 3000 miles across the USA?
Then 3000/60 = 50 days

Saying that I used to bike over 100 miles a day!

By going slowly you can achieve the same things as the solar racers - they are racing after all


----------



## piotrsko (Dec 9, 2007)

Think power racers kids cars, but on a huge scale. Gearing for torque will be your friend if you can get small very high rpm motors.

What chemistry of battery doesn't matter, charge efficiency does. No point in generating 2 kWh if you can only store 1.7.

Weight matters. Loose everything over say 50 lbs, transaxle, seats, most of the pan, fenders. Think Baja. Think motorcycle tires. Does it have to look like a bug? Or is dune buggy acceptable?

My $.02. YMMV


----------



## SunBug (Sep 12, 2014)

I have the tires, they are new Nankang 135s, tiny and overinflated.
The car will have fenders, but no bumpers. Its going to be a normal looking bug but with a big roof rack.
Speed around 30 to 40 mph, it will be a slow trip..
Kinda need the transaxle, its not a real street legal bug without it..


----------



## ga2500ev (Apr 20, 2008)

SunBug said:


> Thanks for the advice, its a real challenge..
> 
> Drive only at night and fold the panels out and manually align them all day


Probably a solar tracking controller would be a better idea. You are going to have to sleep during the day if you are driving at night.



> GT Panels in series with a MPPT charge controller, thats some advice I can use.
> 
> ...Got it.
> 
> The rest is gonna be tricky..


It wouldn't be a challenge if it was not tricky...


> As for bringing a generator, that falls under cheating in this scenario and then its no longer the SunBug.
> 
> The Bug can only be propelled by sunlight gathered along the way.


What about other renewable sources? There may be some spots where wind is available. Others where you may be able to use hydro.



> Thanks again everyone, keep the advice coming. Should I not use a AC motor?


Yes you should use the AC motor. The AC motor gives you regen capability which you are definitely going to need.

What you cannot use is lead acid. You goal has to be a cost be damned project. Your biggest enemy is weight. Lead acid isn't going to cut it.

A compromise with cost and weight in 2014 is Nissan Leaf battery modules. The modules sold by hybridautocenter come in at $0.26 USD per WHr.

ga2500ev


----------



## Sunking (Aug 10, 2009)

Laws of physics is a bitch. A 200 watt solar panel weighs 30 to 35 pounds and takes up just over 1 square meter or more if the panel efficiency is less than 20%. FWIW 20% efficient panels are expensive. 

A 200 watt solar panel at best in Summer in AZ can only generate 1 Kwh/day under ideal conditions stored in a battery. Mounted on a vehicle at best 500 watt hours per day. 

a lithium battery that can store 1 Kwh/day weighs in at 20 to 23 pounds. So for each 200 watts of panel comes 50 to 60 pounds of dead weight to haul around in a 2000 pound vehicle on top of that. You want a 1000 watts of panels requires 300 pounds of extra weight. Charge and sleep during day means head lights at nights robbing you of battery power. 

So what is your vehicle efficiency, 300, 400, or even as high as 500 wh/mile. Just how far can you drive with say 4 to 6 Kwh/day in a 3000 lb vehicle with high drag? 

Bet you one years salary I would smoke your butt on a bicycle and go cross county in a years less time than it will take you after spending 10's of thousands of dollars on equipment, food, hotel, loss of wages, etc.... 

That is why there are no solar vehicles on the market. 

With that said I make a lot of money on solar power, but I would never use it personally.


----------



## Sunking (Aug 10, 2009)

Duncan said:


> Hi Scott
> You won't have a lot of energy - BUT it takes less energy to go slowly - aerodynamics also becomes much much less important


Sounds good on paper huh? You just eliminated using the US Interstate Highway System where minimum speed limit of 55 mph is posted.


----------



## SunBug (Sep 12, 2014)

All excellent points.

I am just trying to push the envelope of whats possible and make automotive history the way people used to do it one hundred years ago at the birth of the automobile with long transcontinental endurance runs.

My chase team/support staff can all be on bicycles! No chase van needed (lol)

I don't have deep pockets, but I plan to rely heavily on sponsors whose logos will be prominently featured all over the SunBug.

Keep the advice coming, I like the automatic panel tracker idea..

Headlights and taillights and license plate lamp are all LEDS, which won't use much power.


----------



## SunBug (Sep 12, 2014)

Sunking said:


> Sounds good on paper huh? You just eliminated using the US Interstate Highway System where minimum speed limit of 55 mph is posted.



It is possible to travel across the country without hitting the interstate, and I plan to avoid them entirely..


----------



## Sunking (Aug 10, 2009)

SunBug said:


> It is possible to travel across the country without hitting the interstate, and I plan to avoid them entirely..


Sure you can. The routes will be much longer, with much steeper grades going through mountain passes. The upside is lots of lots of towns to go through and slow things down.


----------



## Hollie Maea (Dec 9, 2009)

SunBug said:


> All excellent points.
> 
> I am just trying to push the envelope of whats possible and make automotive history the way people used to do it one hundred years ago at the birth of the automobile with long transcontinental endurance runs.
> 
> ...


It's cool that you are looking into what is possible, and trying to push the envelop. These are important things for people to do.

But when you are done looking at the numbers, you will find that it is, in fact, an "impossible dream".

When you could be beat by four guys pushing an engine-less bug across the country, you aren't really making history.

Sadly, it won't get much better any time soon. Even if you got panels that were at the theoretical limit of what a single junction device can output, you would still be facing a many month long journey.

Solar panels are really great, and are one of the most important devices of the next century. But they belong in big stationary applications with tons of surface area. Not cars.


----------



## SunBug (Sep 12, 2014)

East bound and down, loaded up and truckin',

WE'RE GONNA DO WHAT THEY SAY CAN"T BE DONE

We've got a long way to go and a short time to get there.

I'm east bound, just watch ol' "Bandit" run.

Keep your foot hard on the pedal. Son, never mind them brakes.

Let it all hang out 'cause we got a run to make.

-Jerry Reed


----------



## Hollie Maea (Dec 9, 2009)

SunBug said:


> East bound and down, loaded up and truckin',
> 
> WE'RE GONNA DO WHAT THEY SAY CAN"T BE DONE
> 
> ...


Fair enough.

So what's your strategy? I would recommend listing your problems and your ideas for solutions. Use real numbers, and no hand waving.


----------



## SunBug (Sep 12, 2014)

The way I see it, there are two ways to respond here, tell me why it won't work, or look at it as a fun engineering challenge with plenty of problems that need to be solved.

And theres no way I can solve them without this collaboration and of course, cash ..

Checking some stats, I see that each state has their own minimum interstate speed limits, with some as low as 40mph, so theres a possibility I might get to use some of those routes, but I plan to avoid them if I can..

So far, I have a general agreement that an AC motor should be used,(BUT WHICH MOTOR?) Lead Batteries are out, and Panels ground tied in series to get around 100v of charge,and solar tracking..night driving with LEDs, day stopping and charging, avoiding interstates..


----------



## Hollie Maea (Dec 9, 2009)

OK, Engineering challenge. Really, that means collecting a bunch of relevant numbers. You need:

1. Air resistance/speed curve data.
2. Rolling resistance/speed curve data.

That will show you the most efficient speed to travel at. Keep in mind for 1. you need to know how your panels will be mounted.

You need to find out what your weight really will be, and how slowly you can conceivably accelerate. Your motor will need to be geared to be at peak efficiency for that acceleration.

You need solar data for whole route, for different times. Figure out how long the trip will take, and make a tentative schedule, adjusting solar output accordingly.

Once you have some numbers and a plan, get some components and test your assumptions. Adjust accordingly.


Is it possible to drive across the country in a solar bug? From a technical feasibility standpoint, yes. It's also possible to crabwalk across the country. From a practical standpoint, it might come down to whether local officials along your route will tolerate you spending a lot of time on the shoulder. Route planning is going to be tricky--probably the most tricky part of the whole thing.


----------



## SunBug (Sep 12, 2014)

Hollie Maea said:


> OK, Engineering challenge. Really, that means collecting a bunch of relevant numbers. You need:
> 
> 1. Air resistance/speed curve data.
> 2. Rolling resistance/speed curve data.
> ...


Routing will have to avoid mountains, too, I doubt I will have much climbing ability..
And the cops, thats a whole other story, they might not take too kindly to me just soaking up rays by the side of the road..all part of the challenge, I guess..


----------



## samwichse (Jan 28, 2012)

Maybe a lightweight aluminum trailer that's just panels? You could probably add 3m^2 constantly exposed, double that with some kind of unfolding mechanism.

But added rolling resistance and the terrible aero of the bug becomes even worse.


----------



## SunBug (Sep 12, 2014)

No trailer, and now thinking of no roof rack either, all panels stow inside the bug for less wind resistance when underway..


----------



## Nathan219 (May 18, 2010)

http://www.renogy-store.com/mobile/...ng-100db.htm?gclid=CNTY8faC3cACFYhefgodqz4ANg

These panel are much lighter and simiflexible 


Check out what these students did

http://editorial.autos.msn.com/blog...-build-world’s-first-solar-powered-family-car


----------



## Duncan (Dec 8, 2008)

Hi Sunbug
You will need to reduce your speed
Speed is NOT your friend

Going slower will enable you to go further each day
You will need to be looking at 20mph - 40 is definitely far too fast


----------



## SunBug (Sep 12, 2014)

Duncan said:


> Hi Sunbug
> You will need to reduce your speed
> Speed is NOT your friend
> 
> ...


Excellent advice. I would much rather go further than faster..
Looks like I'm going to need one of those triangular "Slow Moving Vehicle" placards for the back of the SunBug, the kind you see on farm equipment..


----------



## Sunking (Aug 10, 2009)

SunBug said:


> Routing will have to avoid mountains, too, I doubt I will have much climbing ability..


Impossible, there is a little thing called Great Continental Divide aka Rocky Mountains to deal with. There is no way around it other than a boat around south America. Then there are a few more along the way depending if you take a northern or southern route. 

Lowest point on the Great Divide is up in Wyoming at 7432 feet. The gentlest grade is along I-40 near Gallup NM at 8400 feet. 

No mattery which route you will have mountains to deal with, no way around it.


----------



## SunBug (Sep 12, 2014)

I guess that means whatever vehicle I build, it needs to make the grade.

Maybe I can get my own reality show on TV

Call it "Slow and Quiet" 

Every week you get to see me negotiate yet another dusty town, complete with angry cops and toothless methed out locals. 
Sounds like fun!


----------



## Duncan (Dec 8, 2008)

"Making the grade" is another place where slow is your friend

If you are climbing you will be able to do less miles/day
But you will get it back on the downhill

Aerodynamics - less important at lower speed - so a roof rack or trailer to transport your solar array may be the best way


----------



## SunBug (Sep 12, 2014)

Duncan said:


> "Making the grade" is another place where slow is your friend
> 
> If you are climbing you will be able to do less miles/day
> But you will get it back on the downhill
> ...


The roof rack is definitely back on the list, I can't do without it..

Thanks for all your advice and comments, ALL OF EM!!!


----------



## akseminole (Jan 5, 2014)

http://store.evtv.me/proddetail.php?prod=180wsolarpanel

180 watts, 6.6 lbs each. 

Why would you even Consider using a 30lb solar panel? 
Ten of these would cost you ~66 lbs granted, you most likely would never see the 1.8kwh of charging potential, but maybe you might get 1kwh.

It only charges a 48v lithium pack, but if you could used contactors or really heavy duty switches to put half a 96v pack in parallel(for charging), maybe this would be worthwhile?
If this were possible, is it possible to run more than one of these chargers in parallel with the others so you could say, have one of these charge controllers per panel?


http://genasun.com/all-products/sol...ium/gvb-8a-li-lithium-solar-boost-controller/

I'm sure my hare brained ideas are full of holes waiting to be found(I'm no engineer), please, open them up to the world so I'll know not to waste my time.

On a side note, it would be really neat if the EV community were able to exert some kind of pressure on this (Genasun) company to build a solar charge controller that would charge a 96, 120, 144v lithium (lifepo4) pack like this 48v unit. 
Especially if you could make them charge in parallel with multiple panels, in essence similar to the way that grid tied systems now can use micro inverters tied to each panel so that one (or more) shaded panel doesn't bog down the whole systems production.

But I also understand that this would be a niche product that most likely wouldn't have That wide of appeal. 
All the grid tie proponents will say why don't you just power from the grid and shunt your solar onto it during the day.

Pretty much I see it as more of a limp home mode/off grid type product for the (likely) very small number of survivalists/preppers who are into EV for gas/oil independence for TEOTWAWKI circumstances.


----------



## piotrsko (Dec 9, 2007)

On route: follow railroads. They avoid more than 2% grades. There IS a southern flat route around mountains which is why Arizona and New Mexico's borders are shaped the way they are. Thank southern Pacific for that.

If you have enough publicity, you can pretty much get away with flouting the law. Can't see where parking in a lot to charge would be illegal. Maybe tie into cancer awareness or something. There are people walking across the US for God's sake.

Unless you have a pre 68 bug with swingaxles, you don't need the transaxle to have suspension.


----------



## dougingraham (Jul 26, 2011)

I should just tell you this is a completely impractical idea up front but lets keep an open mind and work some numbers.

Schedule from beginning of June to end of July to maximize the solar available. This might give you 10 hours of full sunlight if you take a southern route. If you have those flexible panels you are talking about and you come up with a lightweight frame to hold them for your daylight stops lets assume you get the full 1.8kw for 10 hours and you manage to keep 90% of it in the batteries. That would be about 16 kwh. If you use the lightest RC hobby packs to store the energy (199 wh/kg) that give a minimum pack weight of 80 kg (177 lbs). If you strip down the bug to get rid of everything you don't need you I could imagine 1500 lbs. If you keep your speed down to 30 mph at that weight you can probably make 150 wh per mile traveled. This means a daily distance traveled of 107 miles. Daily travel time of 3.6 hours. Traveling half that speed might net you more distance traveled but probably would not double it. Headlights and required running lights are going to cost about 5 amps from the 12 V system which is about 60 watts. This will not be a hugely significant load as over the 3.6 hours it would use 1.35% of your battery capacity (about 1.44 miles.) If you slow to 15 mph your travel time goes up to 7.2 hours and you might get half again as many miles, perhaps 150. This would make your 3000 mile trip take 20 days in the best case. Would a timeline like that be acceptable? I have given every calculation the benefit of the doubt so rolling in all the things that can go wrong you will probably see double this travel time.

Now you should build the car and do some testing to find out what you can really do. The batteries I mentioned will cost $16819.71 plus shipping. So do your testing with something less expensive. Actually you should verify the solar energy collection info first. If those numbers are way off then none of the rest of it matters. I mean if you can't actually collect and store 16kwh per day there is little point. Buy one panel and measure the output under similar conditions. You could store the energy in old car batteries if you want. This part will scale well when you go to 10 panels. And if you can come up with a way to do 20 panels and double the batteries you would almost cut the travel time in half.


----------



## Hollie Maea (Dec 9, 2009)

dougingraham said:


> Schedule from beginning of June to end of July to maximize the solar available. This might give you 10 hours of full sunlight if you take a southern route.


He'll need a tracking system to get that many peak hours. Without it, 7 peak hours is the most you'll ever get. That number goes down the farther you get from the Southwest and from June 21.

An array of 10 of those SunPower modules Jack is selling would be an area of 13 x 8.5 feet. So they won't be trivial to wrangle. Probably would need a foldable roof rack, unless you deploy it on the ground. Either way, a tracking system would be impractical. You could probably get a few more Kilowatt-minutes out of it by repositioning the modules periodically throughout the day.


----------



## nimblemotors (Oct 1, 2010)

Maybe call it "Dumb and Dumber".
Maybe get a sponsor from the Department of Mental Health on how stupid people can be to draw attention to themselves. 

Step 1 is to come up with another challenge that has more meaning. 
Like the record for going across the country in the fastest time in an EV,
so you need a fast efficient car and fast charging and lots of charging stations. This encourages people to build more efficient cars, more charging locations, etc.



SunBug said:


> I guess that means whatever vehicle I build, it needs to make the grade.
> 
> Maybe I can get my own reality show on TV
> 
> ...


----------



## Sunking (Aug 10, 2009)

Hollie Maea said:


> He'll need a tracking system to get that many peak hours. Without it, 7 peak hours is the most you'll ever get. .


Sorry guy, but I design off-grid solar professionally. There are very few places on earth that get that kind of sun hours even with a Tracker.

There is a thin slice of southern AZ and New Mexico in June/July receive up to 6 Sun Huors, and that rolls back to 3.8 Sun Hours in December/January. However even that is optimistic because those numbers are for fixed installations at optimum orientation and tilt angles. You are not going to get that on a moving vehicle. Maybe half that.

Accross the country 4 Sun Hours is average daily year round Insolation. Live in a place like Glomy Doomy Seattle in winter and you get 1 Sun hour for 4 months out of the year, and summer only peaks at 4 Sun Hours. 

If you use LFP batteries, MPPT charge control, with a 1000 watt of panels at optimum orientation and tilt, you are looking at around 3 Kwh of usable energy in a day. Use a PWm controller and about 2 Kwh/day. 

Those are the physical facts that cannot be changed and you have to deal with. IMHO impossible to work with. I think you would stand a better chance installing a huge sail on a car and get across country faster.


----------



## SunBug (Sep 12, 2014)

Sunking said:


> Sorry guy, but I design off-grid solar professionally. There are very few places on earth that get that kind of sun hours even with a Tracker.
> 
> There is a thin slice of southern AZ and New Mexico in June/July receive up to 6 Sun Huors, and that rolls back to 3.8 Sun Hours in December/January. However even that is optimistic because those numbers are for fixed installations at optimum orientation and tilt angles. You are not going to get that on a moving vehicle. Maybe half that.
> 
> ...


Wait a minute here! You speak of a "Moving Vehicle" remember thats not part of the scenario, during the day I am stationary.
Just soaking up rays, and aiming panels and resting..


----------



## SunBug (Sep 12, 2014)

Of course, when it comes time to buy all this stuff, I gotta go with Dereck , even if he hates the idea..

Of all of your off-grid solar systems that are stationary, with trackers, do any of them produce six KW daily?

How about one half that size that can be stowed and folded on a rack?


----------



## Sunking (Aug 10, 2009)

SunBug said:


> Just soaking up rays, and aiming panels and resting..


Well not so sure that is a very good idea at all. 

You have very little power to start with. If you charge batteries during the day, you only get to use roughly 75 to 80% of that power. The other 20 to 25% is lost in conversions and storage. You would be better off using the panels to drive the motor directly without loosing energy in controller and batteries. The sun is strongest between 11:00 am and 1:00 pm. The rest of the day power output will be low.

You would be better off waiting until the sun is high enough and strong enough to move the car on sun power alone for a couple of hours each day then shut down and repeat next day. Use the off hours to charge what you can. That cuts down on battery requirement weight. 

I do wish you luck, but if odds are given at a casino I would bet against you even at 100:1 odds I would not risk it on you.Well maybe $100 to take a chance and strike it rich.


----------



## SunBug (Sep 12, 2014)

Dereck,Out of all the commenters, yours have been the best, and I really need you as a sponsor! I will put your logo on the car and everything. But I understand if you have to pass on that one. 

I really liked that last one, maybe the challenge is to figure out which motor I can run off of just straight sun juice and make the batteries a secondary system..

Maybe you should bet on me, because if you design the system, you increase the odds of victory!!


----------



## onegreenev (May 18, 2012)

SunBug. I sent you a private message. Sunking, The idea presented in a few posts about a small battery pack may not be the best idea. If he is up on the mountain and ready to come down he will only be able to regen what the pack can hold. He needs a good pack to insure he has ample capacity to hold the most possible on those real long downgrades where he could put in a fairly large amount of energy. I also suggest that he use a VW Single Cab Bus instead of the Bug. The Bus has the ability to hold a decent pack and the ability of holding a fair amount of panels in the bed that he can fold out for charing while stationary. I also suggested he be open for at least charging from those folks that have solar on their homes that have setups that actually fulfill the full amount of home needs. Not just those that only have some panels and some grid. At least he can still say he has only charged with solar like he wants. The Bus can handle the cargo weight with ease and with stock gearing he can still go slow but climb and pull like there is no tomorrow. I suggested an AC-35 and a good 96 volt 18kWh pack should be minimum. If he finds some real nice 300 plus Watt panels that are light weight he could easily carry enough panels to unfold for daily charging. In the summer I get 42kWh worth on a clear day with our 7kW Solar array. So it is actually possible to do this if he plans on summer driving and yes he could charge during the day and drive in the evening. It would take a good amount of planning but I see its possible. I don't think too many would sponsor the event but its still doable if you are fully set on making it work. 

Pete


----------



## SunBug (Sep 12, 2014)

onegreenev said:


> SunBug. I sent you a private message. Sunking, The idea presented in a few posts about a small battery pack may not be the best idea. If he is up on the mountain and ready to come down he will only be able to regen what the pack can hold. He needs a good pack to insure he has ample capacity to hold the most possible on those real long downgrades where he could put in a fairly large amount of energy. I also suggest that he use a VW Single Cab Bus instead of the Bug. The Bus has the ability to hold a decent pack and the ability of holding a fair amount of panels in the bed that he can fold out for charing while stationary. I also suggested he be open for at least charging from those folks that have solar on their homes that have setups that actually fulfill the full amount of home needs. Not just those that only have some panels and some grid. At least he can still say he has only charged with solar like he wants. The Bus can handle the cargo weight with ease and with stock gearing he can still go slow but climb and pull like there is no tomorrow. I suggested an AC-35 and a good 96 volt 18kWh pack should be minimum. If he finds some real nice 300 plus Watt panels that are light weight he could easily carry enough panels to unfold for daily charging. In the summer I get 42kWh worth on a clear day with our 7kW Solar array. So it is actually possible to do this if he plans on summer driving and yes he could charge during the day and drive in the evening. It would take a good amount of planning but I see its possible. I don't think too many would sponsor the event but its still doable if you are fully set on making it work.
> 
> Pete


Single cab buses are awesome, but I can't afford one, they are expensive as hell !

I do have a nice bug thats lightened, with new Bonneville Salt Flats rated tires and its a 1967, so I gotta keep the transaxle.

I know a lot of you think this is a really stupid idea, and I fully accept that, and I am grateful for any input. Many Thanks..


----------



## onegreenev (May 18, 2012)

Not a stupid idea but may not be practical or possible using the Bug. The issue is being able to carry enough solar panels to do the job adequately. But the Bug would make a great all around EV. We'd be happy to help if you decide to just do that. Even on a budget it would be doable. If you have the Bug already your on your way to a nice EV. Budget EV's I'd suggest a DC setup. Still suggest lithium batteries. If you can secure a wrecked low mileage Leaf you could have an excellent pack for pretty cheap and even be able to sell off other components to offset the cost. 

I got a single leaf pack for only $3k. Fully usable. Nearly new. Under 400 lbs for a nice 22kWh pack. Perfect. 398.4lbs

Pete


----------



## DavidDymaxion (Dec 1, 2008)

Something else to consider is wind. You could stow a windmill that you put up when you are parked. Also study the wind patterns, you might be able to go with the winds in the morning, but not at night, or vice versa.

Yet another idea: Put in some bicycle pedals and generate electricity as you go. No, it won't be much but it'll be comparable to a solar panel.


----------



## Duncan (Dec 8, 2008)

Sunking said:


> Well not so sure that is a very good idea at all.
> 
> You have very little power to start with. If you charge batteries during the day, you only get to use roughly 75 to 80% of that power. The other 20 to 25% is lost in conversions and storage. You would be better off using the panels to drive the motor directly without loosing energy in controller and batteries. The sun is strongest between 11:00 am and 1:00 pm. The rest of the day power output will be low.
> 
> ...


Not sure if you are correct
It depends on making an array that can withstand being driven,
I believe a fairly large array would be better off soaking up the sun
(despite the inefficiencies) 
compared to what would have to be a much smaller array on the vehicle

Would need to make some "models" - but I am envisioning something like a tent folded out with the panels at a good angle - then moved during the day to maximize energy

I don't see panels attached to a vehicle and being driven being able to absorb anything like as much power


----------



## Ziggythewiz (May 16, 2010)

Late to the thread and haven't read most, but one thing to consider for a solar vehicle would be a trailer. Yes, it adds weight and drag but done right it should only add ~30% while providing 5x the solar.

something similar:


----------



## onegreenev (May 18, 2012)

Ziggythewiz said:


> Late to the thread and haven't read most, but one thing to consider for a solar vehicle would be a trailer. Yes, it adds weight and drag but done right it should only add ~30% while providing 5x the solar.
> 
> something similar:


Makes perfect sense. Way lighter than using a VW Bus. I suggested the single cab because he rejected the idea of a trailer. You could even make a manual tilt mechanism you crank up or down to change the needed angle for best performance possible.


----------



## joeblack5 (Apr 21, 2009)

What a great plan,

If you go for the tracker; may be you can set your van up on larger parking lots and set the steering wheel in a tight circle. Let a very small motor roll the car forward while you sleep. Although it might get hot in the bus. Some safety stuff and you have a one axis tracker.

I have not hear you about wind power if that is cheating?
There are some catamarans with savonius rotors . It might have its own challenge but that is what you are about.

May be wallmart or samsclub parking lots would sponsor you with some food and a safe place to sleep during the day.

You can also see ( cheating) by contacting solar panel houses along your trip and charge up from them, contact me if you need a charge in State College,PA. If you let your setup charge in the winter and deliver back to the grid then you have proof that your van made the electricity, you only pick it back up during your trip in the summer ( longer days) time.

The 20 mph , make it 16 and you would get a farm tractor approval then you can tow as big of a setup as you want.

I think you will get it dun when time is on your side.

Good luck.

Later J


----------



## Sunking (Aug 10, 2009)

Doh, why didn't I think of this earlier?

Correct me if I am wrong but I recall you will have a Chase and Logistic team travelling with you?

Make one of the vehicles a Van and slipstream his butt.


----------



## Karter2 (Nov 17, 2011)

Sunking said:


> Doh, why didn't I think of this earlier?
> 
> Make one of the vehicles a Van and slipstream his butt.


OR... Put some fat RE magnets in the back bumper of the van and use regen brakes to hold the gap !


----------



## nimblemotors (Oct 1, 2010)

A better idea is to use Peltier Modules to generate electricity from the heat differential from the black asphalt and the air above. Just line the underside of the car with the modules and it will power itself down the road on a sunny day, no pesky solar panels. I say it is impossible, so you must do it.


----------



## samwichse (Jan 28, 2012)

nimblemotors said:


> A better idea is to use Peltier Modules to generate electricity from the heat differential from the black asphalt and the air above. Just line the underside of the car with the modules and it will power itself down the road on a sunny day, no pesky solar panels. I say it is impossible, so you must do it.


This is not a good idea at all.


----------



## arklan (Dec 10, 2012)

joeblack5 said:


> I have not hear you about wind power if that is cheating?
> There are some catamarans with savonius rotors . It might have its own challenge but that is what you are about.


get a really big savonis/lenz2 on the trailer and park next to main highways and let all the passing cars wake spin the vawt for u


----------



## Karter2 (Nov 17, 2011)

Taking the Solar generating kit along with you is like an ICE carrying a drill rig and fuel refinery along with it !
The logical solution is to just build a nice efficient stationary Solar array at home to "upload" power into the grid, so that you can "download" that same power from the grid at stages along the your trip.
That way, you can argue you are only using solar harvested power that you have simply "stored" temporarily in the grid.
This is the way most "green" power companies work.


----------



## ga2500ev (Apr 20, 2008)

Karter2 said:


> Taking the Solar generating kit along with you is like an ICE carrying a drill rig and fuel refinery along with it !
> The logical solution is to just build a nice efficient stationary Solar array at home to "upload" power into the grid, so that you can "download" that same power from the grid at stages along the your trip.
> That way, you can argue you are only using solar harvested power that you have simply "stored" temporarily in the grid.
> This is the way most "green" power companies work.


The failure in the concept of this idea is the fact that the grid uses a mix of energy producers. So while it's true that the OP would be injecting solar only into the grid, the output that is pulled is much more likely to be produced from coal, natural gas, or nuclear than from renewable sources.

Also there is a marketing aspect to the original plan. No matter how you spin it, it really isn't very interesting to have a "solar" car that you plug into the wall to charge.

So getting back to the original problem I think the way to improve the feasibility is to improve the efficiency of solar generation. The quickest way to do that is to move away from PV for electricity generation and look into solar thermal options for generating electricity. For example this technology review describes a couple of systems developed by MIT grad students that use concentrated solar collectors to generate steam to drive turbines to generate electricity. The first one is interesting because virtually all of the parts are standard ICE auto parts such as power steering pumps and alternators to generate power.

A foldable mylar umbrella parabola could easily be used as a concentrator. A vaccum solar collector and oil as a heat transfer media can again easily generate temps in excess of 400 degrees F for creating steam.

All that would be required on the road is access to a source of water for steam generation and cooling. Set out your umbrella, pump water through the system, and take a nap while the sun recharges your battery bank. Then drive at night.

Looks like a winner to me.

ga2500ev


----------



## Sunking (Aug 10, 2009)

Consider solar contributes less than 1% of energy demand in the USA is insignificant and does not reduce any emissions makes the argument a moot point.


----------



## Karter2 (Nov 17, 2011)

ga2500ev said:


> The failure in the concept of this idea is the fact that the grid uses a mix of energy producers. So while it's true that the OP would be injecting solar only into the grid, the output that is pulled is much more likely to be produced from coal, natural gas, or nuclear than from renewable sources.
> ga2500ev


 By that line of thinking, any cash you draw from an Auto Teller, or even over the counter at your bank, is not really your money..its drug money, pimp money, or mabe even from Arms sales ?
The "Green" energy corporations have been selling us "Eco solar power" straight off the "dirty " grid for years. You can even choose to have "Wind energy" from the came power line ?
Sorry but if i pump 20kWhr of solar power into the grid "Power Bank" today, i feel perfectly entitled to draw that 20kWhr out tomorrow as "Solar Power" when its raining, even if i am 1000km down the road.


----------



## onegreenev (May 18, 2012)

The Solar Panel Trailer would be best. Or a VW Bus to carry the panels. Be sure to not have a high voltage system and have your charge controller set to charge your battery bank when sitting. Build a simple system that uses a hand crank system to deploy the panels and align for the best performance possible. I have a 7kW system on my home. Today with all the smoke and overcast skies we still got a solid 30kWh collected. My daily use in my Leaf is like 12kWh worth. So a good system of panels you CAN carry is possible. Not every day will be a good solar day. But it will work.


----------



## Jared (Apr 18, 2009)

Most commercial solar panels used in housing have efficiencies 15-20%. With cars square footage is a much bigger limiting factor - with the Australian Solar challenge the top teams use triple junction cells with efficiencies 30%+. You'd need a solar trailer to generate the necessary power, not enough panel space on the VW. 

I'd also agree with the suggestion to drive during the day and not night. Storing energy in a battery and then utilising it is going to be less efficient than driving off it directly. You'd also reduce the size of the battery required.


----------



## dougingraham (Jul 26, 2011)

Jared said:


> I'd also agree with the suggestion to drive during the day and not night. Storing energy in a battery and then utilising it is going to be less efficient than driving off it directly. You'd also reduce the size of the battery required.


The problem with driving during the day is you simply can't do it if your vehicle is a VW bug. You could probably make a car that looked like a bug that weighs a few hundred lbs but it isn't a bug. A real bug is too heavy and not possible to collect enough energy to go faster than a few miles per hour for a few hours at a time. With the car constraint you are pretty much limited to driving at night when it is cool and calm. The route is going to be across the southern US in the middle of June and July. You don't have the energy budget to operate air conditioning. You could carry enough of the thin panels with some sort of folding holder that would allow you to prop them up on the ground at the correct angle to properly collect the energy. The size of the array that you can carry is the first thing to figure out. Then you add a battery pack that is just the right size to hold all of that. I am estimating that 200 miles per day is not impossible, just difficult.

If there is a chase van that is allowed to carry the panels then it should be no problem to make a couple of hundred miles per day. The logistics of finding a place to park with the panels deployed will be a big issue.

Good Luck!


----------



## nimblemotors (Oct 1, 2010)

driving at night requires having lights on, headlights are going to suck up all the energy.
It is just a dumb idea, plain and simple. If we have the coming apocolypse and all you have
is a vw bug and some solar panels and you kids are being held hostage in NY and they 
want a solar vw bug in exchange, THEN it might make sense to attempt.


----------



## Jared (Apr 18, 2009)

dougingraham said:


> The problem with driving during the day is you simply can't do it if your vehicle is a VW bug. You could probably make a car that looked like a bug that weighs a few hundred lbs but it isn't a bug. A real bug is too heavy and not possible to collect enough energy to go faster than a few miles per hour for a few hours at a time. With the car constraint you are pretty much limited to driving at night when it is cool and calm. The route is going to be across the southern US in the middle of June and July. You don't have the energy budget to operate air conditioning. You could carry enough of the thin panels with some sort of folding holder that would allow you to prop them up on the ground at the correct angle to properly collect the energy. The size of the array that you can carry is the first thing to figure out. Then you add a battery pack that is just the right size to hold all of that. I am estimating that 200 miles per day is not impossible, just difficult.
> 
> If there is a chase van that is allowed to carry the panels then it should be no problem to make a couple of hundred miles per day. The logistics of finding a place to park with the panels deployed will be a big issue.
> 
> Good Luck!


I was thinking the car would need to be stripped right down to the bare minimum, and fibreglass panels and polycarbonate windows. By solar trailer I meant something like this:









With an efficient solar array mounted on a trailer, efficient charger, motor and battery pack and so on I see it as doable. It'll be difficult and expensive, but not certainly not impossible...


----------



## Duncan (Dec 8, 2008)

Hi Jared

You need to balance the aerodynamic loads of the trailer with the panels deployed verses the losses in the battery

I haven't done any fine detail BUT I consider that I could arrange a much larger solar receiver if it was stationary than I could if it had to handle the dynamic loads of moving

You may lose - 10 to 15% in the battery in / battery out 
But you could start with two or three times the collector size

Nimble
Do the sums - headlamps are insignificant compared to motive power - and then there are LED headlamps


----------



## dougingraham (Jul 26, 2011)

nimblemotors said:


> driving at night requires having lights on, headlights are going to suck up all the energy.


LED Headlights on low beams = 3.6 amps. Required 4 LED running lights at 0.4 amps totals 5.2 amps times 12 volts = 62 watts. Somewhere between 4 and 5 hours of operation to equal one mile of range. 



nimblemotors said:


> It is just a dumb idea, plain and simple.


Dumb, no. Impractical, yes.


----------



## Karter2 (Nov 17, 2011)

dougingraham said:


> If there is a chase van that is allowed to carry the panels then it should be no problem to make a couple of hundred miles per day.!


 This makes less sense from a self solar powered journey viewpoint , than the suggestion of a homebased solar set up , and a "energy exchange" from power outlets along the route.

Maybe just have that "chase van' with a big , soft , pusher bar on the front !...or a ton of RE magnets in between them to claim "no contact" assistance !


----------



## dougingraham (Jul 26, 2011)

Karter2 said:


> This makes less sense from a self solar powered journey viewpoint , than the suggestion of a homebased solar set up , and a "energy exchange" from power outlets along the route.
> 
> Maybe just have that "chase van' with a big , soft , pusher bar on the front !...or a ton of RE magnets in between them to claim "no contact" assistance !


If you have watched the Sun Race college competitions they have some awfully strange rules and seem to go to great lengths to find ways around them. This kind of thing is not too far out there compared to what you would expect.

It isn't a practical dream, but it also isn't impossible. And there are a number of ways to do it, none easy, or inexpensive. The biggest cost will most likely be in personal time making the journey as it will take somewhere between 15 and 30 days if things go well.


----------



## Vhclbldr (Feb 8, 2014)

I just finished reading this entire thread and a few things came to my less-than-experienced mind:

I like how Duncan recommended starting out confirming the charge capability of the panels as a starting point, and agree that testing each aspect separately makes a lot of sense.

I was surprised at the negative comments ("stupid"? Not cool) from some members, and am glad that even wild, outlandish ideas can produce an intelligent discussion (and allow us to say, "I don't think this will work, but here is my knowledge about the concept that may help".

Although the route will be critical, and crossing elevations challenging, nobody said anything about deserts. Stopping there to recharge - even with a support team - could be daunting.

Regenerative energy capture would allow some range extension, but a careful route analysis will determine its viability (long downhill runs are good, but mild flats not so much)

Could you combine systems? Use a solar-oven-steam-generator-thingy while driving to directly boost the output of the batteries that will be charged while sitting?

Remember, driver comfort is important, too. Make sure your trip doesn't become a descent into hell. Or the Nevada desert.


----------



## akseminole (Jan 5, 2014)

I have stumbled across several links that I think are relevant to this thread.

http://www.emarineinc.com/products/AERL-RACEMAX-MAXIMIZER-MPPT-Solar-Car-Controller-600B.html

http://www.emarineinc.com/products/AERL-COOLMAX-SR-45A-48%2d132V--MPPT-Charge-Controller-SRHVW.html

http://www.emarineinc.com/categories/Battery-Equipment/Super-Capacitor-Battery-Booster/

http://www.emarineinc.com/products/96V-Electric-Drive-Solar-Charging-Kits.html


----------



## arklan (Dec 10, 2012)

whole time i was following this thread i was thinking to gut the beatle and put bicycle wheels on it and limit speed to 50kph


----------

