Revisiting a Push Trailer

[springsguy]

The old thread I started on this project has gone stale......So I'm back to show the latest Push trailer design I've done and to see if anyone else is into this concept.
I used a Nine Continents System on 48 v 12 Ah SLA.........about 20 mile range with pedaling and 17 mph on flat hard surface with no pedaling....I've hit 27 mph pedaling and mid 30's on slight downhill.
It carries plenty of cargo and has no noticeable effects on the bike with exception of braking.

I would love to hear from anyone else who is working on a Push Trailer or has an interest in one.
see more at http://electricbicycletrailer.com

[Kurt]

There are a couple of good things about the push trailer. I like how you don't need to play with your standard bike. just slap on a throttle and some kind of plug to the trailer and your good to go. most push trailers are custom made so motor style and configuration is open to what ever you want to build it around . battery placement can be were ever you design it to be. You can get the weight down very low also.

Its easy to transport your bike by car as the bike its self is just a standard weight and can fit to a bike rack. trailer can go in the trunk.I think bob style trailers are the best design. Not much drag on a single wheel and easy to avoid pot holes and so on.

I sometimes run a little bob trailer behind my bike to tow around extra battery's or other junk it tows real nice even with a lot of weight in it but can bounce a little over things like speed humps.I like the way it quickly disconnect from my bike and even folds down on its self.I have a little brushed hub motor in a 16" wheel that would be ok and the way the trailer attaches to the bike it would push the bike from its axle line. i might try it out some day if I get time.

the bad points are that you are usually limited to 16" wheels.The bike is a little harder to turn around in tight spots.The trailer puts a but more load on your kick stand so have to watch for stability when parked. A trailer on a bike attracts attention.Good for cars not so good for cops.Forget about man handling your bike up onto something or over something.

I like your home made trailer its the best I have seen and a Quality looking build well done.







Kurt.

[PaulM]

Kurt, your passenger doesn't look too impressed . . .

I am working on a push trailer as well, bob style, powered by a converted alternator and RC ESC, driving the rear wheel with a #35 chain. I plan to make it suspended and am using the swingarm and wheel from an old YZ80 motocross bike. Batteries will be 2x 18 Ah and 2x 20 Ah SLA's, which I plan to mount on either side of the swingarm to keep most of the weight on the trailer wheel. I can already tell that the trailer will not be very light, but hopefully the weight will be manageable. Braking performance remains to be seen, but I am already thinking that if I leave the alternator field powered, it will create a "compression braking" effect when I let off the throttle. If that does not work and the bicycle brakes are unsafe stopping all the extra weight, I will have to figure out a way to actuate the drum brake still in the motorcycle wheel!

See the link in my signature for my build thread.

[spinningmagnets]

good search terms: push trailer, pusher trailer, and power trailer

http://endless-sphere.com/forums/viewtopic.php?f=3&t=2798


http://endless-sphere.com/forums/viewtopic.php?f=6&t=8996

[spinningmagnets]

Here's another, made from a childs Razor scooter:
http://endless-sphere.com/forums/viewtopic.php?f=3&t=4917

[spinningmagnets]

You can always upgrade later to a more professional-looking set-up, but I believe the push-trailer is the absolute cheapest way to get started with electrifying a bike, And you can easily get any performance aspect you want (top-speed, hill-climbing, max range) and all without hacking the bike at all.

This pic is from a "thrift store" experiment I did. Used hand cart was $10, 20" BMX was $20, and the sprocket adapter was from a thick aluminum skillet which was ONE DOLLAR! I was looking for an ultra-cheap/no-welding solution for the sake of conversation. The 47T sprocket was from a "trash day" bicycle BB.

[ktronik]

Dug up from a old post is my 'pushy pusher', it looks a little different now & soon to have, better storage & a new Infineon controller, as I am RPM limited @ the moment due to the banfang being a geared motor & not liking the basic controller...banfang is light & small & seems to last in a 16" wheel without striping out the plastic gears... old post below...

Built up a 24v /26" banfang into the rear of my BOB trailer...running from a 18A (modded for 48v) controller, powered by 9Ahr 48v LiFe pack, on my Surly Karate Monkey 29er. Custom cruze control & dynamo driven LED lighting system





Bike fully built (even wheels) by me, running solid rear axle & bob nutz.







to the left of the gear numbers is the 'GO' button



& the magnetic brake reset (which cuts the cruze control throttle button when braking)



Very basic cruze control using 1/ 5v relay & a feed back loop (latch link), I added a dropper diode just in case my controller did not like the full 5v, so now it sees 4.3v on throttle signal input. The controller is modded with a 12v zener reverse bias to the LM317 (PCB reg) so it still sees 36v + a few caps were changed. Extra heatsink added to controller box just in case.

Custom lighting system by me, driven from dynamo hub, with circuit to give 12.4w rather than 3w, in to cree R2 bin LEDs we get 750lm output (HID lights ~450lm)





Also to let people see how easy the martin basic circuit really is, I have re-drawn it, with a pic of what the parts look like the way I build it (dead bug style)...each step is the same circuit, just re-drawn so its easier on the brain...



as its a 26" hub in a 16" wheel, it goes up any hill I throw @ it... top speed up a hill 27 km/hr & 29km/hr on the flat...

enjoy

Ktronik

[Kurt]

Kurt, your passenger doesn't look too impressed . . .

Yes we had just ridden about 20km and she was about to fall asleep. Its about the only problem taking a child on a bike they fall asleep easy.I think i need a child trailer not a push trailer LOL.

Kurt.

[spinningmagnets]

Here's one more made from a Currie-Drive unit:

http://endless-sphere.com/forums/viewtopic.php?f=2&t=4699

[spinningmagnets]

Here's one more. This is from the "atomic zombie" website. They sell plans to cut and weld your own frame for bikes of many different configurations. Notice the rear suspension arm, this model is named the "Cycle Bully"

http://www.youtube.com/watch?v=cU2i6fn4Dp4

[nineball]

I think it's great idea, I made a comment in a recent post about wanting more range/distance without towing a trailer of batteries,this would be great for just that. Pile on a few car batteries and ride a hack of a ways. Nice job

[spinningmagnets]

Found one more! This guy (Rassy) has since moved on to a two-wheeled recumbent and a one-wheeled trailer. I assume its to be narrower for navigating tight paths. There's an interesting part where he's helped in building a "resistive short" (long piece of wire wrapped into a coil around a plastic pipe) that allows the trailer motor to cheaply become a brake on downhills, helps prevent bike brakes from becoming hot on a long downhill. (edit: I learned the proper term is "plug brake") Here's the thread:


http://endless-sphere.com/forums/viewtopic.php?f=3&t=703&start=0

[spinningmagnets]

One more pusher trailer for the data file (pics would not load)

http://www.schultzengineering.us/hybrid.htm

[torker]

Good find. I love the wine box. Have you built a pusher trailer spinning magnets? This interests me. Especially a budget approach using some off the wall motor. Although a hub motor in a 16 or 20 inch wheel would free up room in the trailer for batts. etc.

Oh looks like you did/ a trash day hack together trailer..

[spinningmagnets]

Click on the home page, and then click on "Fahrradanhänger mit Elektromotor", then scroll down to the bottom of the page to see a dozen or so German drücken-Sie-Anhängers (push-trailers)...

http://www.bobtec.de

[spinningmagnets]

From ES member " chvidgov.bc.ca "

http://endless-sphere.com/forums/viewtopic.php?f=7&t=13995

[spinningmagnets]

From ES member " dontsendbubbamail "

http://endless-sphere.com/forums/viewtopic.php?f=6&t=5317

[JEB]

The pusher trailer I use the most consists of a, 1.9hp 24v dc Ego motor, driving a jack shaft with 2 bmx freewheels, to two 10" go kart tires (both wheels driven), the Li battery pack is mounted on a full suspension frame that also has the store/carry basket on top.

I normally use it to push a Mad Max Evo II trike, through a swivel mounted above the rear wheel.

The other pusher I built uses a Ego motor also, direct drive to a single 10" tire, with ajustable spring loading "training" wheels (one on each side of drive wheel), full suspension also, 2 deep cycle 75amphr lead acid.

[spinningmagnets]

From JEB, He emailed me a pic of his set-up from the next post just above this

[Julez]

Hi Guys!

I finished my push trailer some time ago, here is a picture:



Here is the build thread:
viewtopic.php?p=216230#p216230

[vanilla ice]

^Shifter electrically actuated by a drill, neat.

[spinningmagnets]

16" wheel with a scooter tire, 1000W @48V, SLA batteries...from damonjackson_spl in Australia

http://endless-sphere.com/forums/viewtopic.php?f=28&t=15328

[Lyen]

16" wheel with a scooter tire, 1000W @48V, SLA batteries...from damonjackson_spl in Australia

http://endless-sphere.com/forums/viewtopic.php?f=28&t=15328

Very nice! Was it easy when you attach the trailer with the weight of the batteries & motor to the bike while it is standing on its vertical position?

[damonjackson_spl]

21kg of batteries (20ah at 48v) in the trailer was like re learning to ride again, very sketchy and trashed the trailer!! 9kg (7ah at 48v) of batteries much much better but 1000W keeps hitting low voltage cut out so still trying to get the ah to weight ratio just right, simple answer is lipo...

very very good power and massive low end torque for climbing, flats is slow around 25/30km/h but can climb very steep grades!! for my commute of 15km from 0m to 556m above sea level is nice for me!!

might be better with 500W motor and 7ah batteries?

[PeteCress]

...the bad points are...

What happens when you are turning and accidentally hit the throttle?

Seems like the trailer would try to upset the bike.

?