Introduction: Portable Solar Generator on a Bike Trailer for Burning Man

Picture of Portable Solar Generator on a Bike Trailer for Burning Man

AKA Solar panel On Wheels, aka Post Apocalyptic Power Wagon, aka Bike Dance Party USA, aka I should hook up a electric motor to this bike cuz the trailer is so damn heavy from the battery...

First let me start by saying this is not a plan on how to exactly build an Off Grid Solar System. Depending on what type of solar module or modules you use or what type of charge controller and battery you use. The plan can come out completely different.
This is more of an overview of a simple system I built with what I had available. But.. It does stand as a very good model for a simple Off Grid system that's got a little bit of umph behind it.
I have ran off this trailer such things as a small refrigerator, a skill saw, several drop lights, a Sawzall with a drop light, ghetto blaster and 3 strings of xmas lights all night, electric tea pot, and the list goes on.
So the story goes something like this. I was going to Burning Man with my work to build 9 solar arrays. First a 14k array for our camp to serve as a public charging station for electric art cars, camp batterys and, anything else under the sun (laptops, ipods, flash lights, vibrators, what ever). Then we built arrays to power 3 more camps and finally we fitted 5 major art installations with smaller solar arrays (1 to 2 k).
I needed a way to run power tools to build the other arrays so I came up with the idea to retrofit this cheapy kid bike trailer that I got at a thrift store for 8 bucks with a 80 watt solar module, 150 amp hour battery, charge controller and, 400 watt inverter.
The idea is that I can attach my trailer to my bike with the solar junk and ride to other camps that don't have power and work on stuff. Now that I'm home I can ride my bike to anywhere there's a party happen'n and make the scene.

Step 1: Stuff You Need

Picture of Stuff You Need

First lets me say that this isn't really about how to build a solar bike trailer. That's why I am not getting into every little hole to be drilled and screw to be screwed. It more an illustration on how to set up a very simple Off Grid solar system and the components necessary. You should be able to take this simple plan and build it into almost anything (camping trailer, RV, apartment balcony, little cabin in the woods, ect.).
My goal was to not buy anything new for this project. I found it all left over in my garage from other projects or at my work in the warehouse in some boxes of old parts. I know that most people don't have solar modules and and charge controllers laying around.. but I will try and give you some idea on how to spend as little $$ as possible. I figure if you bought this all new it could cost from $350 to $600.

TRAILER Build one!!! (search "bike trailer" on this silly site), garage sales, Craigs List, thrift stores, ect.. The One I used is a cheap one. I took off the plastic body and cut it in half. Then I bolted it back on the frame and bolted scrap plywood over the wheels to serve as a strong platform.

SOLAR MODULE (aka Solar Panel) This one is a 17 volt 80 watt. I scrapped it from a downed freeway sign that had solar lighting. We are going to be using a Module around 17v because we are running a 12v battery. You can look for them used on Ebay or hunt for a new one online. I just searched and found new ones from $156 to $250 (google "solar panel 80 watt")

INVERTER This is a regular car inverter that you could plug into you cig. lighter outlet. It changes the 12 volt DC(like a car battery) into 120 volt AC (like your house) This one came from Home Chepot and is rated at 400 watts that's plenty for a system this size.

CHARGE CONTROLLER Now this is a can of worms. The charge controller protects the battery while it is charging. It keeps the right amount of juice coming in and sometimes even going out. The one I am using is a Trace C40 (read here for more about this CC) it is total over kill for this project. Trace also makes a really good smaller one that would have worked just fine the C12 (more about the C12) The C40 cost around $150 new and the C12 about half that. They are high quality pieces of electrical equipment and will last for years. You can buy a simple 12volt charge controller online for $20 to $30 that will work.

BATTERY You will need a 12 Volt deep cycle battery also call a marine battery. In theory you could use a 24 volt battery but you would need a 24v inverter and module. Or two 6 volts ..or.. or.. I'll save you the class on batterys.. that's what the interweb is for. I am using a sealed gel type battery for UPS systems it is 150 amp hours (that pretty big 80 ish lbs.) I get them free from a buddy that builds UPS systems every once in a while.. that's why I'm using this battery. It retails around $350. I could use a lighter battery like Li-Ion and it would weigh only 30 lbs but it would cost $2000.

MOUNTING HARDWARE The hardware I used was left over from residential solar installations. It is light weight and very strong. You can use a scrap of steel strut, u brackets, nuts, bolts, and fender washers.

WIRE I used leftover scrapes of multi strand 10ga wire

Step 2: The Trailer

Picture of The Trailer

Like I said earlier any trailer will do, just make sure its strong. I bolted the plywood on good by drilling holes in the steel frame. Then I used some old book shelf brackets to hold the vertical plywood up. That's where I'm going to mount the electrical components. The solar module is mounted with really nice solar industry specific parts from ProSolar but you can use stuff in your garage or hardware store. I did a quick search and found some random PDF with pictures of steel strut and hardware see chapter 15

The Battery is held on with an old nylon strap buckle. I think a bungy cord will do.

Step 3: Elecrtrical Componets and Wiring

Picture of Elecrtrical Componets and Wiring

I made up a really simple wiring diagram to show you how I wired this thing.

Step 4: Well Its Pretty Much Done...

Picture of Well Its Pretty Much Done...

Remember this was more of an illustration on how a simple off grid PV system works... not so much of a how to build the darn thing. I hope this got your "wheels turning"


benslimmyb (author)2015-02-02

Hi could you let me have your email. I have a proposal and want to know if you are interested

RajeshP (author)2014-08-01


Tater Zoid (author)2014-07-08

Hi, did you have to clean off the playa dust often? Would it still generate power during dust storms? Thanks.

ayousef (author)2011-01-29

I am currently working on a mobile solar power trailer (see example photo) which will have two 250W monocrystalline panels (500W total power), an MPPT charge controller, 1000W inverter, 2 12V200AH GEL batteries, and BOS. I am not sure whether to use a 12V system or 24V system which will dictate the selection of my various components. Can you shed some light on this ? Thanks a lot !

astral_mage (author)ayousef2014-06-19

go 24 volts an use a 24 to volt 12 step down converter.

Talk about an AMAZING build

GOLBABA (author)ayousef2011-08-18

Hi, some PDF files on this subject you to send me an email

legamin (author)2014-05-13

pretty cool! I'd put an axle and bearing system under that trailer that would serve two purposes.. 1. Lessen friction for pulling. 2. Lessen the eventual likelihood that those kiddy wheels and axle will fail catastrophically under battery and panel load.

Ps: Accordion design for multiple foldout lines of panels. Get triple the wattage in the same storage.

internethotspot (author)2011-04-08

Would this work to charge an electric scooter bike? Sounds like a good idea to be able to ride your electric bike with a lightweight trailer in tow, park and charge while walking about. Or maybe even keep it charged while driving (is that possible)?

I'd love to know this too! Just bought a scooter and it takes ages to charge for about an hours worth of scooting !!

GOLBABA (author)JackIsted2011-08-18

Hi, some PDF files on this subject you to send me an email

TOCO (author)2010-05-05

Where did you get the inverter?

PCfreak (author)2009-07-16

Id like to know what u used to draw out your wiring drawing and cool Indestructible

veggiecycle (author)2009-04-29

Sound good to me

ozetzioni (author)2008-10-31

Hey, I am building a pedal generator bike with a battery. at the end of the day i want to transfer the electricity i made of riding into a bigger battery and then use it for lighting equipment... anyone knows of a method to transfer the electricity from one battery to a bigger one without losing voltage or too much energy???

luck (author)ozetzioni2008-11-13

how big is the battery u r charging, how big is your transfer battery and what r the voltages. were are puting the battery on your bike and how big is that space i might be able th help but i need this bit of information

ozetzioni (author)luck2008-11-23

hey thanks,
I want to use a 6 or 12V bat (on the bike) and discharge it (probably through an Ultra capacitor / voltage amplifier) to a bigger 12V battery.
now - the bike's battery can be portable (add on) or built-in - what you think is more efficient... I really need some help with this,

luck (author)ozetzioni2008-11-25

i would use the the 12 volt battery on the bike and make it removable for repairs or just dont want it on there, plus plus if you use the 12 volt on your bike you should not need a voltage amplifier because you are putting 12 volts into another 12 volt battery you would just need to find a way to keep the big 12 volt battery from back feeding power to the smaller 12 volt.

radiochemist (author)luck2009-04-13

look for some current blocking diodes on ebay that they use for solar panels. if you have a good charge controller you could probably hook use that to charge the larger battery faster than the battery alone by just hooking up the small battery where you would put the solar panels. just double check everything to make sure the voltage and amperage limits aren't exceeded.

lilykoart (author)2009-04-07

this diagram has been what i have been searching for!!! i know zil about wiring. i understand better by pictures :) thanks for putting it up!

Yerboogieman (author)2009-04-03

I'd just get a bunch of smaller lighter batteries.

KT Gadget (author)2008-09-30

this is cool! wish i had the money to get one of those high wattage solar panels. oh well worth trying with the smaller ones. if possible, you could find smaller panels (like 20 or 40 watts) and make a fold-up solar panel so it saves space and be able to get into those tight turns (maybe even lighten the load a little). other than that, cool ible!

ElectricMan1 (author)KT Gadget2009-03-29

Just go to The Electronic Goldmine! You can get photovoltaic cells for cheap! Do you have any knowledge of electronics? Because you can just build your own.

KT Gadget (author)ElectricMan12009-03-29

yea i have some knowledge of electronics and i can ask my dad if i need help with stuff. but yea ill check to see if they have some cheap, or better if someones selling some of the better ones for cheap somewhere.

ElectricMan1 (author)KT Gadget2009-04-03

Like I said, Electric Goldmine!

thatsgreat2345 (author)2009-01-14

Nice, I would think about combining this with the Pedicab, could get a little music going.

You know it really wasn't smart putting all that expensive equipment on to a cheap plastic trailer. Because if the trailer breaks, your screwed. Other than that, great idea!

woodfinery (author)2009-01-07

Very nice! With the economy tanking we need these great ideas!

kingstonsdad (author)2008-10-05

Here, here. you have made so easy for me. I was going to give up trying with solar, but Im going to give it go with a couple of ideas I have. Cheers Ill keep u posted on how I go

Arrrgh (author)2008-10-05

Thanks for the instructable -- makes solar seem a lot less intimidating.

veggiecycle (author)Arrrgh2008-10-05

I'm glad you get it... I'm just trying to get people interested and more familiar with the concept. There is no way I can do a Off Grid system justice with an Instructable. There is just to many ways to do it... I would have to do 1000 of Keep you eyes out. I'm going to do some more real soon. Thanks

qwertyboy (author)2008-10-05

doesn't it get easier to pedle after you get going? i think it would

dombeef (author)2008-10-04

Also put a motor connected to the wheel so you get twice the power

phildavi (author)2008-10-03

good effort

macrumpton (author)2008-10-02

Very nicely done. If you put the motor on the trailer it could push you along, and leave the bike lightweight for when you are not towing. It also means you can use it with other bikes and scooters if you can come up with a nice way to attach to generic vehicles. Heck, all you need is a unicycle with a robust way to join it to the trailer (for stability) and you have a electric trike. I have seen several other electric trailers (without the solar) so I know it can work.

cooldog (author)2008-10-01

bike wheel generator you should add this to both the wheels

veggiecycle (author)cooldog2008-10-01

I checked out you gen. when you put it up.. I like it... But 80 watts of PV gives me tons of power. More power is not what I need.. its less Thanks but not on this project..

ac-dc (author)veggiecycle2008-10-02

I didn't read the charge controller spec sheet in depth, but you may get nowhere near 80W from that panel. 80W would be the peak output under ideal conditions. You wrote it was a 12V panel, how was this determined? Normally to charge a 12V SLA battery (which has a float voltage at 13.2V or higher) you need a roughly 16 to 18V battery or even higher when it's a higher wattage panel. The higher the input voltage the faster it can charge the battery or charge it at all when sunlight is poor. For power when you aren't riding this is better than a wheel generator, those are usually only 6 or 12W each and too inconvenient for site use, but obviously more cumbersome and less fun riding the bike with it attached. You might want to determine the charge rate and discharge rate to decide if the battery size is optimal or if you can use a smaller battery to reduce weight and drag. Angling the solar panel differently will also effect drag and you might consider a more streamlined piece of plastic added right in front of the battery too, or at least tilting the solar panel the opposite direction.

frollard (author)cooldog2008-10-01

Cool: not to be smart-assed, but yes, lets take a bike thats already weighted down with a 'heavy' trailer with a 'sail' on it, and add 2 more resistive loads; pedalling that thing would be a joy! Great build veggi!

Painkilla05 (author)2008-09-30

Very nice! now you just need an electric bike.

chalky (author)2008-09-30

This burning man thing look absolutely brilliant! i only wish i didnt live on the other side of the world so i cannot go:) ps/ oh and by the way, great instructable too!

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