Electric Bikes - I received a 1500 dollar grant to build an ebike. Advice requested (first build)

As mentioned in the thread title (and in a recent thread that got attacked by a troll) I have a 1500 dollar grant from a utility company to build an ebike.

My latest plan is to construct it using an adult tricycle. It's a much more stable platform for students to help in testing the bike (it will be student built with supervision).

I visited the local Trek dealer today and found a pretty good bike that has potential, and since it has a strong cargo area it would serve the school well as a small light utility vehicle as well.

I'll also be riding it for six months as part of a cost/benefit analysis.

this is something i've been researching quite a bit as i'm interested in eventually building an electric vehicle, or electric- assist.

a point from your old thread- Why are hub motors a must? while in a lot of situations they're ideal, but it does limit your options quite a bit.

there's probably quite a number of threads on www.ecomodder.com (http://www.ecomodder.com/) that could help, as well as a few instructables about building electric motorcycles, motor powered bikes, etc to give you more places to search.

I'm not sure if hub motors are a must - drive through-gears types such as Cyclones, or parasitic motors such as Curries are definitely another possibility, or even e-trailer-pushers etc.. There is also some new interest in friction drives out there. There are only so many places on a bike to put a motor and battery though, and other variables such as waterproofness (bad on Cyclones), bicycle balance, need for panniers, need to pedal (affects batteries in frame type designs), drive-train spacing issues, stealth (bad on Curries - quite loud) are important. I think simplicity and quietness are both valuable. Trikes are cool because you can carry an awful lot of battery, and the extra weight seems to offset the stability issues of trikes to some degree. But they are expensive unless you get a fairly unstable delta trike under 500 bucks. Anyways there are a lot of successes out there, and many many failures when it comes to homebuilt ebikes - it's most useful to do a lot of research at a place like the endless-sphere electric vehicle forums, where you can tap into a great deal of experience. There's something about the indestructibility of a direct drive well-sealed hub motor that just "seems right".

Thanks for the advice, Chvid. Great advice. I did find a bionx PL-350 for $1664, which is about $200 less than the usual price. That might come in handy.

Some other things I have to figure out are power usage and draw (in terms of figuring out exactly how much power is being used). I heard that you can buy a device at Home Depot that you can plug into the wall and then plug a charger into that device, and it will tell you exactly how much electricity you used. The main point of this project is to do a six month analysis of the cost and benefit in comparison to a car. The project starts Monday with my weight, the price of gas (my car is on fumes right now, which is perfect), the amount of energy used, carbon footprint, etc. It will all get written up and reported. The students and I do the math, input the data, etc. I'm pretty excited, and the energy company is excited too.

Some other things I have to figure out are power usage and draw (in terms of figuring out exactly how much power is being used).

These "Watt's Up" type meters are great for monitoring several aspects of your project's power usage. I use them on all my bike and trike builds.

http://www.powerwerx.com/tools-meters/watts-up-meter-dc-inline.html

Thanks. That's a great start. I imagine that using an electric bike is significantly cheaper than driving a car, and I have to show the numbers.

i'd say go with a BMC 600W kit and 50V10ah lifepo4. Total cost would be about 1400(264 less than the bionx 350w) you can run it at 900w warrantied, although it's rated at 600w continuos it takes 900 easily. Then you'd also have the choice of front or rear wheel motor, also it already has a connection for a cycle analyst so you can buy one and it'll make your calculations far easier.

Thanks. That's a great start. I imagine that using an electric bike is significantly cheaper than driving a car, and I have to show the numbers.

A lot cheaper!

After several years of riding E-bikes, my average power usage with a moderate amount of pedaling seems to be about 20 to 40 watt/hrs per mile, or .5 amphours/mile from a 36 volt battery pack.

I'm sure it will run a bit more on a three-wheeler, but maybe not, as I'm usually pushing higher speeds than you might want to go on a trike.

Just a reminder that this will be student-built, and they will help with calculations.

I found an excellent meter for measuring the flow of electricity into the charger, so that's taken care of.

But I also found this tricycle online: http://www.amazon.com/gp/product/B001PH7RVM/ref=s9_simh_gw_p200_d0_i2?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-2&pf_rd_r=1XVH5T642GN27VW13GA0&pf_rd_t=101&pf_rd_p=470938631&pf_rd_i=507846

It seems like it would be an excellent solution.

In terms of SLA batteries (separate topic from the above tricycle): I have access to electricity on both ends of the commute and can keep it plugged in when not in use. SLAs are so easy to get and so inexpensive, that they might be a good idea on a tricycle (in which weight is less of an issue).

Any thoughts on that?

If you ever get concerned about weight, then LiFePo4 batteries should work well.
As it happens, I teach as well (I assume you do since you mention students)l, and I think this is a splendid idea. I hope you don't mind if I pursue it myself. This would be a cool idea for my (very small) campus instead of having the crews drive around in trucks.

I've seen pictures of trikes in the tunnels of the Fermi National Lab...in the cyclotron (of course). The maintenance folks use them to carry themselves and tools through the long tunnels. I don't know if they were electric, but I bet you could ask them.

I'm pumped up about it. The students get to help build it. It's a win-win situation for everyone. I get to be the test subject, which will be challenging (with winter coming on) but fun. The cost savings won't be huge, as I drive a compact car and by road it's only 6.5 miles to work. But still, it will be neat to see the difference, especially in terms of the carbon footprint.

It would be amazing for the students to get the chance to build a lifepo pack with BMS. Soldering flat leads etc. Dangerous of course.

For maximum education the kids should learn about power bridges in a controller and data collection, from motor rotation sensors to temperature cutoffs.

If you have the time then see how far you can get without buying a simple kit. Even if you do buy an off-the-shelf controller it would be fun to walk through the different motor types and their most efficient power supplies.

AC induction all the way!