Recommended electric bicycle kit for educational workshops?

[gravoid]

Hello,

I'm going to be teaching a physics-based workshop for high school students. They'll learn about the physics of bicycles, and during the month they will be converting their bicycles into electric bicycles.

I'm posting this as an open call for suggestions on which kit I should choose. The easiest, slickest kits on the market are way out of our budget, so really I'm looking for the cheapest kit available that would be worth pursuing (not the absolute cheapest!). As this is a hands-on workshop, assembly steps are not an issue; in fact, the more work involved, the better opportunity for instruction (i.e. building a wheel up from a hub rather than buying a complete wheel). Friction drives are totally an option too, if it helps get the price down. We're more interested in the hands-on opportunity than the power of the end product

Also, if it makes sense to buy individual components instead of kits, I'm game for that as well.

For reference, we should have about 5-10 students in the first workshop, so any info on companies that will sell discounted in quantity (or to a nonprofit) would be great.

Thanks,

Simon Graves
Wellspring Community School
Bellingham, WA, USA

 

[OneWayTraffic]

How about brushed DC motors, BMX pegs as a friction drive roller, a simple controller/switch and a 12v deepcycle battery. Doesn't get simpler than that.

 

[dogman dan]

I'd say go both ways. Have some build cheap friction drives, and others build wheels with inexpensive gearmotors from bms battery. And maybe others do a Currie motor or some kind of chain drive. Same for batteries. Get some sla's but also get some lipo from Hobby King so they can see the battery tech advances, and maybe some nicads in drill batteries in between for comparison. Once the bikes are built it would be cool to be able to compare how they run on different batteries. You have access to machines to cut parts the kids design?

 

[Drunkskunk]

The simplist kit for consistancy would probably be Ebikekit's 9c kit. I've got no Idea if Jason would give a discount for educators, but I would think he's likely to.

 

[Ypedal]

The simplist kit for consistancy would probably be Ebikekit's 9c kit. I've got no Idea if Jason would give a discount for educators, but I would think he's likely to.

+1 on www.e-bikekit.com Jason would likely welcome such a thing !! with SLA it would be pretty cheap, and you can teach brushless vs brushed tech.

 

[amberwolf]

Well, you might check with Cell-man about some of his hub kits. But the cheapest way to do it is fully DIY, either bottom-bracket (cyclone / stokemonkey / etc.) or friction.

If you go thru my Electricle project blog, at http://electricle.blogspot.com there are a few very cheap DIY ideas.

There are also a number of recent (and older) friction-drive threads here on ES, though most of them are not about repurposing and might not be that cheap to do.

Using brushed motors is simplest, and probably cheapest, because you do not have to use an electronic controller, and can just use switches. In fact, you can have a speed control by switching between battery voltages, although this is not healthy on the batteries, over time. Using a 36V system, you get three speeds, at 12V, 24V, and 36V.

 

[LI-ghtcycle]

This is a very exciting idea!

I agree probably the cheapest way is brushed motors and a simple friction drive, and who knows, maybe if you talk to some of the bigger companies that sell here, maybe they would give you a discount on a hub motor kit!

Hub motor kits are definitely the easiest to install and the most "plug and play" but designing a friction drive would be more educational, maybe look through the "non hub motor" section and see what people have built.

What is your operating budget per child if you don't mind my asking?

 

[adrian_sm]

Hello,

I'm going to be teaching a physics-based workshop for high school students. They'll learn about the physics of bicycles, and during the month they will be converting their bicycles into electric bicycles.

What a great idea.

As this is a hands-on workshop, assembly steps are not an issue; in fact, the more work involved, the better opportunity for instruction (i.e. building a wheel up from a hub rather than buying a complete wheel).
...
We're more interested in the hands-on opportunity than the power of the end product

How hands on?
- Just swinging a spanner
- fabricating parts with simple tools
- custom CNC parts ?

Friction drives are totally an option too, if it helps get the price down.
Also, if it makes sense to buy individual components instead of kits, I'm game for that as well.

Hmm. If it was me running the class I would see two options
1) Get everyone with the same kit/setup
- easier to run the workshop
- possibly cheaper as buy in quantity
- students can help each other out

OR

2) Get a range of different types of e-bikes to build
- more learning experince, as can teach more topics
- students get to free-form learn a bit moe, understanding the pros and cons of technology etc.
- but harder to teach, as everyone is doing different things, some will be easier than others, finish quick, other will take forever.

I would be tempted to go option two if you have the time. You could then tackle, various motor type and drives
- BLDC hub motor, sensored
- BLDC hub motor, sensorless
- brushed motor
- In-runner with gear reduction
- friction drive out-runner

You could also try and commonise the voltage to allow different battery types, which will let you explore battery chemistries pros/cons. And have the different batteries swapped around between the bikes.
- LiPo Example
- LiFePo4 Example
- SLA

For reference, we should have about 5-10 students in the first workshop

Is the aim to have the students ride off on their new e-bikes. Or keep the parts for the next class.
If they aren't taking them home it will be much cheaper, as you don't necessarily need to buy batteries for ever bike, they could be shared. And the batteries are the most expensive bit, unless you stick with cheap SLA.

, so any info on companies that will sell discounted in quantity (or to a nonprofit) would be great.

Thanks,

Simon Graves
Wellspring Community School
Bellingham, WA, USA

I can recommend companies, but it would be easier, once we know which direction you take on the type of kit, level of customisation/fabrication etc.

Good luck. It sounds like an excellent workshop. I hope it goes well.

- Adrian

 

[spinningmagnets]

For inexpensive, it will be hard to beat Solar-Motions brushed friction-drive with SLA batteries. Brushed controllers are much cheaper than the 'more-efficient' brushless, but actually not bad for a starter kit. SLA won't last long if driven hard and deep-discharged, but again, cheap entry into a running E-bike.

Once running you can still upgrade later to brushless, and NiCD/Lithium...

http://endless-sphere.com/forums/viewtopic.php?f=28&t=14387

 

[veloman]

Take a look at my recent builds (link in signature). It would be a good route to go if you have machine shop capabilities. The motor is only $65 at tnc scooters (get the 450w). You could do a bare bones set up with a tandem crank, or get freewheel crank parts from sickbikeparts. Still quite cheap and I have to say, I like going through the gears during an acceleration, like riding a dirt bike.