powered bicycle trailer idea

[vax]

Hello
I had this idea of making electric powered bicycle trailer. Something like this:

or bigger.
The motor would be integrated with axle, something like this http://www.aliexpress.com/item/BM1412HQF-14-BLDC-2200W-60V-brushless-motor-heavy-electric-tricycle-motor-Mini-car-differential-gear-motor/32325045651.html
Batteries under platform
And, the main feature - the throttle would be integrated with connecting link - there's a spring loaded slider. When you start moving, the spring compresses and moves magnet away from throttle hall sensor. So, you never feel the weight of trailer when riding, it's jus follows you under its own power.
Optionally, you could switch to external throttle, in which case it becomes pusher trailer.

 

[borschelrh]

I built a trailer for my ebike to transport my inflatable catamaran on a 4 km ride to Lake Balaton. The trailer loaded weighs around 50 kg and so far has worked well. My only real problem is weight balancing of the boat in the trailer and I have found I need to keep the weight balance forward or it begins to wobble. I don't think it is even remotely necessary to add power to the trailer except as a place to store batteries for longer trips. I chain the bike to the trailer while out sailing. Mostly I just get some people staring at this contraption as it is apparently looks slightly insane.

I built the trailer using an old child carrier and welded a frame to hold the boat.

https://endless-sphere.com/forums/download/file.php?id=121147&mode=view

 

[dogman dan]

Interesting concept for the way it starts powering. It would though, tend to start going if you came to a stop on a hill. The trailer would roll back, and start shoving you. Then stop, then start, then stop. Sounds like it could be a real buckaroo.

Some kind of deadman switch would cure that of course, but I'd say just run a regular throttle would be simpler and safer.

Lots of pusher trailers have been done, but in general I'd say the overwhelming preference is for a nice strong bike, and just pull a trailer. That's what I do myself. Here on ES, we like a nice powerful bike anyway. Real fun to ride when not hauling the trailer for one thing. If you wanted the trailer so your bike can be nice and light when not riding motorized, get two bikes. Pull the trailer with a nice motorized beach cruiser or something, that's not so light.

Nothing wrong with the idea of a large battery load in the trailer. Could be all of it, or just additional range. But if you are thinking trailer to haul lead, forget it. Get a nice light and powerful lithium battery. Hauling lead around is as smart as driving your pickup with a load of gravel on it at all times.

 

[ecycler]

Sounds like you have envisioned the opposite of a "surge brake" trailer. The mechanism for providing braking via a hydraulic master cylinder when the tongue compresses works okay for boat trailers and I guess the opposite concept of adding a spring and hall sensor to activate an electric motor controller to accelerate should work as well, but I don't think I would enjoy the experience of not having manual control over a motorized aspect of my rig. Dan is correct that hills are going to make it a pain in the ass without some level of manual controller or microcontroller programmed support.

 

[amberwolf]

Other than the control method, the idea is sound enough--the surge problem on a slope could be a problem and it wouldnt' take much of a slope to cause it. Might even happen at heavily-crowned intersections, depending on how they make them where you are.

Even if it didn't surge into you and push you forward, it might engage just enough on the slope to cause motor heating while not actively pushing hard enough to get you going, unless you "lock out" levels of assist like those.



One pusher trailer I still intend to make someday is a large wide one for large furniture, appliances, multiple large dogs, carrying my other bike (or trike), etc., where I don't want to or can't pull that weight even with 2WD or 3WD on the bike/trike pulling it, or need the traction of the trailer wheels to get and/or keep going.

Most likely I'll end up using brushed powerchair motors with gearboxes, because they have massive low-speed torque to get me started up from a stop, which is my main concern--once up to speed at 15-20MPH it's not that big a deal to keep pulling it with the bike/trike's own motors, but getting started with several hundred pounds (or more) could be a problem, especially going up any slope.

Using brushed motors, one on each wheel, means I could run them in series or parallel on the same controller, and not have to worry about syncing up multiple controllers to prevent accidentally steering the load with the wheels.

 

[dogman dan]

I like the idea of dual throttles, or maybe a thumb activated switch to control the push.

So in your rig AW, you'd have a way to quickly and positively engage or disengage the additional push from the big trailer.

Push button regen braking on the trailer would of course, be a nice feature.