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Author Topic: "SunnyDream" build. Unofficial LSR solar vehicle build.  (Read 2974 times)
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PatMc
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« on: July 29, 2012, 10:51:18 AM »

Me and the kids are building a 2 wheeled solar powered unofficial LSR (Land Speed Record, not racing).  It is not likely to go faster than the mega-buck university racers, it's for fun and to see how fast we can go.  AFAIK, the fastest solar vehicle without battery assist is 88kmph.  I want to go 89kmh+.  We have 90% of the parts, and the frame should be finished this week.  Testing in August.

If anyone is interested in this kind of technology, PM me.  Otherwise, I will just post a video when we get it running, then attempt to run it at El Mirage, and perhaps Bonneville.  There is no class for it, so it's a Time Only effort.  It's the old school classic:  "How Fast I Make This Hotrod Go?" without spending megabucks.

We are not giving up on diesel racing, but our current truck is going in a different direction that is not compatible with LSR.  It is still street legal, registered, insured, and street driven, and will remain that way.   It will run drags and sled pulls.  Next diesel effort will start with a true SCTA class build, not a street truck.  Someday in the future I hope to give a shot at the Phoenix record.  But that is hundreds of hours and $$$$ away.  I'm already collecting parts for it.  I have the driveline, the HP, just shopping for the best production frame and body to use.

Sidebar - Much of what I'm learning and testing applies to solar power for housing.  When it is done, the panels will hook into the grid and reduce our electric bill when it's not being driven.  It is modular, so the panels are on a very strong (80mph wind+) custom "Ground Mount Frame" that could easily be roof mounted, but hard to take back down to drive it.  So if there is interest is DIY solar power, the build data would be informative.  Next step after the solar, is true electric LiFePO4 race build with no solar.  How do you eat an elephant?  One bite at a time.

« Last Edit: July 29, 2012, 12:20:30 PM by PatMc » Logged
will6er
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« Reply #1 on: July 29, 2012, 05:46:07 PM »

If you get a chance, talk to "Le Triplettes de Bonneville" team. They had an impressive solar array last year.

Will
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RidgeRunner
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« Reply #2 on: July 29, 2012, 09:05:42 PM »

  The battery 'letric M/C liner at Loring a couple weeks ago impressed me.  I've been an engine man most of my life but I have to admit there is a lot of potential in the new 'letric motor set ups.

Ed
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PatMc
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« Reply #3 on: July 30, 2012, 12:27:15 AM »

I'm retrograding.  The first electric car was in the 1830's.   grin  A Roadster is a real newbie in comparison. 

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maguromic
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« Reply #4 on: July 30, 2012, 12:47:03 AM »

Pat, Post the technology and the build of the solar project.  Very intriguing project you have, its always fun to learn something new!  cheers Tony
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Jon
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« Reply #5 on: July 30, 2012, 02:35:57 AM »

Hi Pst

I would be keen to see updates on this.

If your running without battery assist I guess your all over the "Solar Maximiser" circuitry.

I've made a couple for running pumps direct from panels.

Cheers
jon
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PatMc
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« Reply #6 on: July 30, 2012, 08:41:37 AM »

The panels normally sold for home use have a glass sheet on top of them, are about 50lb each, and are 200-300 watts, and about 5.5' x 3'.  The glass rules them out for any kind of auto use IMO.  A mild accident would cost $$$$.

You also have flexible thin film solar stuff.  Look up Unisolar on Ebay or Amazon.  This stuff is amazing.  You can roll it up like carpet, walk on it, put nails in the edges of it, etc.  It's 128w, 15" x 17', and 17 lb?   It's intended to be used as roofing shingles, and built into the house.  However, the output is about 8% efficiency and normal silicon solar chips are about 17%.  So it takes up twice as much room.  I have one of these that will soon power the lights in my trailer with a battery.  It wasn't going to be useful because of the square feet required.  It would be the safest.

So I found semi-flexible panels about 4' x 2' that use the silicon chips.  These are mounted on aluminum sheet, weigh 6.5lb, and produce 105w (measured after MPPT) at noon.  19.0v x 5.56 amps.  I bought 10 of them, which is 80 sq ft.  I had also bought just raw solar chips, and was going to solder them together.  These things are as fragile as butterfly wings.  When I first tried to measure one, it broke in my hand.  It was about .004" thick IIRC.  For the number of cells I'm going to need, this would be silly.  If you break one in the middle of a chain, you must try and replace it.

When I first hooked a panel to a motor, it did nothing.  Here's the funny thing about them.  They only produce power if they have the perfect load.  No load voltage was 20.8v, but zero amps.  Dead short made 0.2v at 5.56 amps.  The circuit that puts the perfect load on them is called a MPPT (Max Power Point Tracking).  This adjusts the resistance the panel sees to optimize the watts it produces.  After I put one of these on, it will make power.

When you do a house, you are running a series of panels at 400-600v DC into a MPPT on-the-grid controller.  Make a mistake hooking a 5000w array together can kill you dead.  Series system are dangerous, since if somehow they see the right load and you're touching it, you lose.  Cover panels when working with them.  

Another weird thing about solar panels, is that you cannot block a small area at all.  If I put my hand in the corner of the panel, the output falls from 105w to 20w instantly.  In some cases it can drop to 10w.

The frame is at Mitch Fabrications being welded up out of aluminum.  We first need to do balance testing with dummy weights.  This is a two wheeler.  It will have a 25' long wheelbase and be 4 feet wide.  Time to take the kids to school.  Will finish later.

« Last Edit: July 30, 2012, 10:01:33 AM by PatMc » Logged
hotrod
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« Reply #7 on: July 30, 2012, 09:07:21 AM »

Quote
Cover panels when working with them. 

Yes indeed, one KW of 12v panels will make very short work of a screw driver put in the wrong place if they are illuminated.
A co-worker of mine discovered that when working on a solar powered communications van the State of Colorado had in the late 1980's.

Sounds like a fun project.

Larry
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PatMc
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« Reply #8 on: July 30, 2012, 09:58:52 AM »

That is why we are not running 190v (all panels in a series), even though it would reduce weight and make more mph.  Although all the high current stuff is 20 feet away from the driver and the frame will be ground, my kids are working on it with me.   Not sure if 190v would kill, but I'm not ready for that kind of testing.  While working on the race truck 4 years ago, I had a 120v device explode in my hands (an extension cord reel).  I was rushed to the emergency room, then they immediately sent me to the Burn Center at UCI.  While I was there, my pancreas shut down, I wrote my last will and testament with a pencil, and they immediately pumped me full of drugs and removed my gall bladder.  In short (pun intended) I was nearly killed by a "safe" electrical device.  Electricity and I are bitter enemies.  But then again, I did a lot of the wiring on our 460vac 3-ph, 600 amp building without being able access the main disconnect (AFTER my accident).

Since there are 10 panels, I can run 19v x 10 panels, or 38v x 5 panels, or 95v x 2 panels.  Ixnay on the 95v.  Not sure if we are going 19v or 38v yet.  Have to build an electric motor dyno to figure it out.  We are aiming at 1.2 HP to the ground.  That might be optimistic, but we will try.

I am not an electrical engineer, I measure stuff for a living.  Most of what I know I learned by reading.  So feel free to add input to this project.  You might save me some money or pain.

« Last Edit: July 30, 2012, 10:05:58 AM by PatMc » Logged
Frank06
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« Reply #9 on: July 30, 2012, 02:25:30 PM »

Hi Pat,

This sounds like an interesting project.  I volunteer up at Loring, tech inspect motorcycles and am the EV guy.  We also have about 5kw of PV panels on our house and I've done a few EV conversions.  I suspect the largest challenge of the project will be constructing the vehicle and minimizing drag and rolling resistance.  If you're working with very low power levels EVERYTHING becomes important!  I'm sure you know this...    grin

I hope you document the build on this site and what a great learning experience for the kids.

Frank
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PatMc
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« Reply #10 on: August 05, 2012, 02:56:02 PM »

Well, our first attempt isn't going to work.  The frame is too flexible, the rear axle needs to come forward.

We started out with junk bicycle parts to get the balance and geometry to work:

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SteveM
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« Reply #11 on: September 19, 2012, 10:24:54 AM »

The concept looks good.  I agree with you that the frame looks too long and flexible.  I'm kind of "into" bicycles - have you looked at some of the recumbent bikes on the market?  You might be able to adapt a long-wheelbase recumbent to work for your project.

The human-powered vehicle racing crowd really knows how to get the most speed out of a 2-wheeled bicycle.

  http://www.recumbents.com/forums/

They just held their Human Powered Vehicle Speed Challenge, which takes place in NV.  It's the "SpeedWeek" of HPV racing.

Steve.
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