Shockdyno's solar E-Zip trailer

[shockdyno]

This trailer was built from two cheapie ($85 ea) Walmart Instep baby trailers bolted together. On board are two 40 watt PV panels wired in series, a 110 Volt inverter, a size U battery box, two 12 VDC charging alligator clips for charging any 12 VDC battery, 24 VDC Sunsaver solar controller direct wired to the Currie 24 VDC bat and a multimeter to indicate when charge is full. Total trailer weight is 43 lbs (without 12 VDC bat).
I am presently residing in the mountains and there is literally no flat land in town. Extensive testing is planned for this Winter while residing in flat Tucson. The stock Currie charger is 1.5 amp charging rate. The trailer should be about 6 amps charging rate. The 12 volt battery can be carried for 110 VAC for wifi coffee shop hopping and sidewalk laptop charging at night and even a printer, or 36 VDC "overvolt" charger for when I am overvolting. The bike can tool around this mountain town for a mile or two and stop for a half hour or so to re-top off the 24 VDC Currie Bat and take off again for a jaunt. No hard data yet until I find flat land.
This stock trailer clears the stock Currie motor for sharp right and left turns except the size U battery box gets in the way for medium right turns in this application.
I'm guessing a 125 lb rider could ride continuosly at 10-15 mph with the Sun overhead here in AZ on flat land. We'll see this Winter with a lower Sun.

 

[D-Man]

Nice. How much does it cost to build one of these? (solar part)

 

[shockdyno]

Thanks,
I got the solar panels for $50 each at a storage locker auction factory sealed in the carton about 6 years ago.
YMMV

shockdyno

 

[mikereidis]

>I'm guessing a 125 lb rider could ride continuosly at 10-15 mph with the Sun overhead here in AZ on flat land. We'll see this Winter with a lower Sun.

Interesting. But that means riding in the hot sun...

Is it easy to keep clean ? I presume it's rain-proof, but rain could kick up mud onto the cells.

Watch out for birds ! They might target your nice shiny cells with you know what.

 

[D-Man]

Yes, how much have you seen the charging amps vary if its cloudy out, partial sun, morning, evening , etc...

 

[shockdyno]

Yes, how much have you seen the charging amps vary if its cloudy out, partial sun, morning, evening , etc...

That's a good question. If I unplug the XLT plug from the Currie bat, the multimeter will show an increase in volts. The panels put out about 30 volts un-plugged and drop down to a couple volts above the battery voltage when the XLT is plugged in. I have nothing to measure amps. The voltage seems to stay at 26-28 volts when a cloud goes over but I am sure the charging amps are minimal.
Bisbee is located a mile high in the mountains about 250 miles South of Phoenix such that the Sun elevation angle is relatively high 12 months of the year. Clouds are a rarity and rain more rare. I knew posting the trailer pix would spurn questions that I can't answer but someone sent me a private message asking if any trailer would clear the E-zip Trailz motor so I posted the pix.
I had the panels on the roof of my house and knew I needed a long bike trailer. The aluminum "work" trailer out of Ames, IA was over $500. I really lucked out that the Walmart Instep trailer fit the panels perfectly as well as bolt together end to end through pre-existing holes in the frame. The pix were posted mostly to share a source of relatively inexpensive bike trailers and their application for the relatively inexpensive E-zip Trailz E-bike. The center of gravity of the whole trailer is really low also due to the "dropped" design of the frame. I'll have some hard solar data this Winter when I migrate to flat Tucson when its not 100 degrees there everyday. Meanwhile I'm staying in very hilly and cool Bisbee until Oct 15.
BTW we have a phenomena here in AZ at some times of the year if your PV panel is facing directly at the Sun that it heats up the panel big time and significantly degrades its performance. Solar homeowners will actually re-direct their panels away from the Sun to maximize their output. Most panels wattage is rated at 75 degrees F.
HTH, from the land of the Endless-Sphere,

shockdyno

 

[How2]

Hey Shockdyno... Thanks a million for posting this! I even called Currie tech support and they could not recommend a trailer that would clear the motor... uggg. I contacted that same company in IA that has great trailers and a hitch and towbar that clears, but not only are they very expensive, they are also backed up with orders through the summer!

Can you take one or two more pictures of your fine handiwork where you bolted the two trailers together and perhaps describe that process?

Also, are you actually able to carry cargo on your solar panels? I thought they were more fragile than that, or do you remove them to carry cargo?

Thanks again, this is a HUGE help to me and other Ezip riders!

 

[dallasfoto]

Wow...I want one! This is quite wonderful.

Your fifty dollar panels make me really want to pursue the idea of a solar charge station awning at school. A science project for the middle schoolers. I really need a "battery info for dummies" book. I still don't understand how much solar power I need to make the Currie charger work right.

 

[shockdyno]

... where you bolted the two trailers together and perhaps describe that process?

Also, are you actually able to carry cargo on your solar panels? I thought they were more fragile than that, or do you remove them to carry cargo? !

Thanks,
No cargo on the panels unless a 3 ply pad on top. If the bike were to make a cross-country type trip, the panels could be raised a foot or so and camping gear stashed beneath I suppose.
Look at the 2nd picture posted and look at the U-shaped cross member and the two 3/8" holes. The trailer frame is perfectly symetrical except for the wheel mount flanges. 2 - 3-1/2" machine bolts through these holes to butt up the two frames. (wheel flanges can be located at the far back of the double trailer to relocate them if so desired) I needed tight cornering in this town of hills and S turns and a shorter overall wheelbase. The heavy bike/battery/me makes it so the 43 lb trailer is not even there except for its slightly added pull on the motor.
Look at the top picture posted and you will see a 1/2" x 1" milled piece of brown Walnut hardwood spacer since the U-shaped crossmembers are not 90 degrees to the rail. The two 3/8" bolts in the pre-existing holes is pinching that wood to keep it in place. I'll add two more bolts thru them if needed later. HTH

shockdyno

 

[shockdyno]

Wow...I want one! This is quite wonderful.

Your fifty dollar panels make me really want to pursue the idea of a solar charge station awning at school. A science project for the middle schoolers. I really need a "battery info for dummies" book. I still don't understand how much solar power I need to make the Currie charger work right.

Thanks,
5 watts does nothing I learned. You would need two 12 VDC panels to charge your 24 VDC Currie. I would suggest the minimum of 25 watts each. (about 4 amps total max) This would potentially charge your 24 VDC bat twice as fast as your 1.5 amp Currie 110 V charger. BTW the list price of the panels which cost me $50 at auction was about 10 times that at that time.
HTH

shockdyno

 

[How2]

... where you bolted the two trailers together and perhaps describe that process?

Also, are you actually able to carry cargo on your solar panels? I thought they were more fragile than that, or do you remove them to carry cargo? !

Thanks,
No cargo on the panels unless a 3 ply pad on top. If the bike were to make a cross-country type trip, the panels could be raised a foot or so and camping gear stashed beneath I suppose.
Look at the 2nd picture posted and look at the U-shaped cross member and the two 3/8" holes. The trailer frame is perfectly symetrical except for the wheel mount flanges. 2 - 3-1/2" machine bolts through these holes to butt up the two frames. (wheel flanges can be located at the far back of the double trailer to relocate them if so desired) I needed tight cornering in this town of hills and S turns and a shorter overall wheelbase. The heavy bike/battery/me makes it so the 43 lb trailer is not even there except for its slightly added pull on the motor.
Look at the top picture posted and you will see a 1/2" x 1" milled piece of brown Walnut hardwood spacer since the U-shaped crossmembers are not 90 degrees to the rail. The two 3/8" bolts in the pre-existing holes is pinching that wood to keep it in place. I'll add two more bolts thru them if needed later. HTH

shockdyno

I see that hardwood spacer. i thought that was a plywood bottom so thanks for the explanation. Is it possible to get a shot of the underside of the trailer? Also, I'm not a tool/home depot guru yet, can you show us a closeup of how the two trailers meet? Even of the hardware used? I'm sure there are folks here that understand exactly what you mean with that explanation above, but I'm such the noob at these things and need a bit more hand holding on the How2's.

Regarding the solar panel setup... that's just amazing! Those 40W panels are $250ea today. You got a great deal there! I look forward to hearing how you experiment with this setup and the ranges you can squeeze out of it.

Thanks again shockdyno!!!! uhhh... do you have dyno powered lights??? just wondering about your nickname there!

 

[How2]

5 watts does nothing I learned. You would need two 12 VDC panels to charge your 24 VDC Currie. I would suggest the minimum of 25 watts each. (about 4 amps total max) This would potentially charge your 24 VDC bat twice as fast as your 1.5 amp Currie 110 V charger. BTW the list price of the panels which cost me $50 at auction was about 10 times that at that time.
HTH

shockdyno

I found this setup at Harbor Freight that says it will charge 24volts and is used on construction sites to charge 18volt and 24volt power tool batteries... hmmmmm. Does this have any promise for charging the 24volt Currie batt pack?

18 Volt to 24 Volt Solar Charger made by Chicago Electric Power Systems
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=95017

Portable folding design
Built-in blocking diode to prevent battery discharge
Charging indicator LED
Easy to transport with built-in handle

Cordless drill sold separately. Overall dimensions: 6-1/8"L x 18-1/8"H x 23-1/4"W; Power cord length and plug type: Two way insulated plug, 10 ft. length

ITEM 95000-5VGA

$85.99

 

[shockdyno]

18 Volt to 24 Volt Solar Charger made by Chicago Electric Power Systems
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=95017

I saw that also the other day but it does not specify watts or charging volts. I'm guessing from the size and price that it is fairly small. I guess it boils down to how fast you want to charge. It took a week of sunlight to charge a 12 VDC 20ah SLA in an experiment with a Harbor Freight 5 watt panel which was $49.95 at the time. Looks like general rule of thumb is about $10 a watt for panel purchase. The weak US dollar is making PV panels still expensive versus the German Euro where the roof tops are filled with panels even with their cloudy weather compared to the USA.

shockdyno

 

[shockdyno]

... where you bolted the two trailers together and perhaps describe that process?

... Is it possible to get a shot of the underside of the trailer? Also, I'm not a tool/home depot guru yet, can you show us a closeup of how the two trailers meet? Even of the hardware used? Thanks again shockdyno!!!! uhhh... do you have dyno powered lights??? just wondering about your nickname there!

A photo of the trailer underside will not actually show you anything except the 1/2" spacer between the two frames. Look again at the 2nd photo which shows the end crossmember. There are four of these crossmembers on the two trailer frames. All four are identical. Do like I did and just bolt one frame to the other using the holes you see in the photo. You will find that the double trailer you just bolted together has a slight kink where they join and the side rails are not in a straight line. You will then figure out where to put the 1/2" spacer to make the two trailers straight. It is barely noticeable and the trailer would work fine.
Summary: You line up two frames so the bolt holes line up. Insert two bolts and tighten. Attach wheels and hook up to the provided hitch on the bike. Unkink later.

HTH

shockdyno http://www.shockdyno.com

 

[How2]

It took a week of sunlight to charge a 12 VDC 20ah SLA in an experiment with a Harbor Freight 5 watt panel which was $49.95 at the time. Looks like general rule of thumb is about $10 a watt for panel purchase.

A WEEK? THAT'S WEAK! LOL!

In thinking about this further, that tool charge setup is for tool batts that have low amp hours in comparison to our Currie batt packs. So it would work, but who knows how long it would take.

One could get really adventurous and keep the costs down by building their own solar panel from broken cells like in this instructable (Dallasfoto, this would be a good project for your students): http://www.instructables.com/id/Make-a-high-powered-solar-panel-from-broken-solar-

 

[How2]

A photo of the trailer underside will not actually show you anything except the 1/2" spacer between the two frames.

That is the part I can't see and don't understand.

Look again at the 2nd photo which shows the end crossmember. There are four of these crossmembers on the two trailer frames. All four are identical. Do like I did and just bolt one frame to the other using the holes you see in the photo.

okay.. got it.. for some reason i was not looking at the crossmember for the join, but rather the side frames. ::headbonk:: Joining the crossmembers to the hole that is already there is brilliant and simple... except for this next part:

You will find that the double trailer you just bolted together has a slight kink where they join and the side rails are not in a straight line. You will then figure out where to put the 1/2" spacer to make the two trailers straight. It is barely noticeable and the trailer would work fine.

Sorry, I don't get this part but it sounds important if the trailer is extended like this and is used more for varying weight loads of cargo. (which is my intended application). If there is a kink that is left after joining the two trailers, I suspect the frames will bend easily even under a light load. I don't, however, understand or see in the photos where a kink would be left. Thanks again for your help!

http://www.shockdyno.com

Nice website... so YOU ARE a gadget guru!!!

 

[fulltlt]

Good work! Could you provide a closer up picture of the area where the trailer hitches to the bike? I'd like to be able to see how it's set up to clear the motor.

TIA

 

[RLT]

I'm really liking this project.
But the thing that concerns me, is: Aren't those solar panels pretty fragile? Wouldn't every pothole risk destroying them, or at least breaking a delicate connection?

 

[shockdyno]

Good work! Could you provide a closer up picture of the area where the trailer hitches to the bike? I'd like to be able to see how it's set up to clear the motor.

TIA

 

[shockdyno]

I'm really liking this project.
But the thing that concerns me, is: Aren't those solar panels pretty fragile? Wouldn't every pothole risk destroying them, or at least breaking a delicate connection?

I was concerned also. The L brackets that attach to the frame sit on 1/4" thick soft rubber grommets to lessen any sudden shock. What really helps is running the tires with 2-3 psi pressure. They compress about an inch and work as a spring. At full speed, the drag is minimized by the tires "humping" up a little bit presumably from centrifigul force. I'm more worried about someone dropping something on the panel or worse yet, ripping off the trailer. As mentioned, it weighs 43 lbs and can be carried quite easily with one hand grabbing the side rail right near the balancing point near the tire.

shockdyno

 

[RLT]

Sounds like a good, simple solution.....
I never even thought of someone dropping something on it.... I can definitely see that concern, now that you mention it.
Maybe some 'chicken wire' mesh an inch or three above it? Wouldn't add much weight, wouldn't block the solar rays by any appreciable amount, yet protect from 95% of the likely things that could be dropped and break it.

Well, good luck with it!

 

[fulltlt]

Good work! Could you provide a closer up picture of the area where the trailer hitches to the bike? I'd like to be able to see how it's set up to clear the motor.

TIA

Thanks for posting the pictures. I couldn't quite figure out the receiver hitch at first. The black objects are chair legs in the background, right?

 

[snowcrow]

Very nice work 8) I'm looking to build a trailer for my 48v system, I'm going to use (4) 20W panels though.

How big is the trailer frame, excluding the hitch and wheels? This will help me in deciding which panels to buy :wink:

Blessings, Snow Crow

 

[shockdyno]

The panels (40w) are each 20"x30". Any wider than 20" would have to mount on top of the trailer frame rails and not nestled between them nice and low. BTW The distance between wheels/tires is 27-1/4". HTH,

shockdyno

 

[snowcrow]

The panels (40w) are each 20"x30". Any wider than 20" would have to mount on top of the trailer frame rails and not nestled between them nice and low. BTW The distance between wheels/tires is 27-1/4". HTH,

shockdyno

Thanks shockdyno,

The 20W panels I'm buying are 14"x 19.5", so I guess I'll be fine with a single row of panels To bad the width not +28", I could have doubled up on the panels and make the trailer shorter. I guess 5 ft isn't realy too long for a trailer, better that than too wide and get clipped by a car

I also like karma's trailer, but I think he may need a bit more solar 8)

http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=235&start=315#p121206

I thought about enclosing the bottom of the trailer and use the solar panels as the lid, a place to store camping gear 8)

Another thing I was planning to do is wire the panels so I can switch them to 12v, 24v, or 48v with a Xantrex C40 charge controller. If I put a huge cap between the solar array and charge controller, it will keep a steady flow of power going to the batteries, even when shaded while riding in and out of shadows.

Blessings, Snow Crow