electric build planning...

here in VA, electric bicycle laws are super dumb. I can't even get to work without breaking 2 regulations.

Hence , I'm building an electric moped. with this 40T chassis. I have a set of mags otw and all the parts I need for handle bars.


The gas tank is pretty well trashed and one silent block mount is damaged, so I don't feel bad hacking it up.

I imagine ill need to beef up the frame and the front suspension, but thats the easy stuff ill do once I get decent estimates for the additional weight of batteries+motor. I do want a chain driven motor hanging where the stock motor would go.

With VA moped laws limiting me to 35mph and 2000W of power, I think I should be able to achieve 35 without stressing the motor right (I don't want the motor constantly running at peak power)?

I also need to climb 9% grades at 25mph (in my hood). outside of my neighborhood, the terrain is maybe half as steep.

I know just enough to be dangerous with electrical systems. I make my own wiring harnesses and test components with a multimeter. So I need reference material to read and examples to reference.

I'm not opposed to making a trike with a sold rear axle Either...

So what I really need help with is choosing components to match what I want todo. Halp?! (edited)

Re: electric build planning...

I thought of doing this to a trash maxi I got for free.

My plan was to get one of the plentiful e-bike conversion kits of ebay, re-lace the hub motor to the 17 inch maxi wheel.

The electric super cub i've seen posted around would be a good source of info and inspiration.

Re: electric build planning...

this is where you start realizing it's pretty cost prohibitive, try to find cheap sources of batteries, and then store it in your basement for years hoping prices will go down.

I've been toying with the idea of trying to make a batterypack from UPS (uninterruptible power supply) boxes. people replace those in businesses fairly regularly and trash the old ones, many of which run banks of Li-ion batteries, which could be rewired to 12V.

I suspect you'll want a real fram mounted motor, especially since you're on mags.

I think you can hit your needs with like a 48v brushless motor. most cheaply, and there are probably 415 420 chain sprockets that can go on those. take care of the RPM for the motor, calculate out final drive gearing in advance cuz that obviously will affect chainline and how/where to mount the motor

I dunno, i've never done it. never had the free scratch to blow.

Re: electric build planning...

I've wanted to do this for awhile. I have good experience with building electric motorcycles. The problem is the cost. Batteries are expensive; I would want to make a custom pack based on what the application calls for using a123 or Samsung cells or something, but each cell is like $12-16. Then you have to cut and spot weld bus bars and insulate properly and all that jazz, and it winds up taking a significant amount of time (depending on how many cells you use and how you configure the cells).

Then you get to the motor controller, which you can save some money on by using an arduino. There's a little bit of a learning curve, and it takes some time but it's not all that expensive and there are tutorials online. A good friend of mine took an XR100 with a trashed motor and threw together an electric conversion using parts he found in our university's dumpsters throughout the years, an arduino, and a 3d printer. That thing kicks ass.

I would definitely put a motor where the original was, that will give you better performance over a hub and more tuning capability. You can actually find 1500-2000w brushless DC motors for relatively cheap online (<$100). The problem with these usually are bad data sheets/documentation. I would just try to make sure that the documentation for the motor you buy is good enough so that you can hook it up without ruining anything.

Here's a picture of the bike I work on racing at Pike's Peak. We placed first in the electric class last year.

Re: electric build planning...

Super interesting, Have any pics without the plastics?

My plan has been to grab one of the trashed ones that shows up on my block weekly, and invest in a new battery. Keep it slow-ish and low key.

Those 300-500W hub motors can rip if you're only on flats ever.

Re: electric build planning...

> Careless Whisper Wrote:

> -------------------------------------------------------

> Super interesting, Have any pics without the plastics?


> My plan has been to grab one of the trashed ones that shows up on my

> block weekly, and invest in a new battery. Keep it slow-ish and low key.


> Those 300-500W hub motors can rip if you're only on flats ever.

Here's a picture of the bike without the lower fairing, you can see about a quarter of the battery pack. We have 938 cells in our pack. On the bottom is the inverter/motor controller. We run a 3-phase ac motor on the bike.

Garbage builds are the best builds; those motors are definitely capable for flat land at decent speeds. I have a few trashed electric scooters I got from the trash that I plan on scavenging parts off of, if I ever get around to it

Re: electric build planning...

I was hoping to use an arduino or something I could program, since I'm a software engineer. Cause then I can add silly things like blinkers, head+tailight, and those UV powered wheel rim glow strips, controlled by buttons or switches.

Re: electric build planning...

Charles Cole (OFMC) /

I spent 3 hours on line last night looking at components. Expensive to say the least. A stealthy ped would be awesome where I live. I'd like a solid 40 mph and 15-20 mile range. Be fairly easy to convert an old moped or frame, at least all the metal work. Wish there were forums for diy electric moped builders.

Re: electric build planning...

Charles Cole (OFMC) /

Another thought I had, was to use a Hobbit format so it could be variated. Any thoughts on that?

Re: electric build planning...

CVT is ill-suited for EV. the torque curve is much too broad. Its likely that Throttle position will determine the CVT's gear ratio, not REVs

Now a motobecane style foot lever for more torque would definitely be great for burnouts, or a low power electric motor setup. Its probably gonna shred belts.

Imma keep it simple. I may use the motobecane pulley just so I don't have to mess with chain tension problems. This would make it easier to add a variator and launch lever later :) (edited)

Re: electric build planning...

> Charles Cole (OFMC) Wrote:

> -------------------------------------------------------

> Another thought I had, was to use a Hobbit format so it could be

> variated. Any thoughts on that?

Last night I accidentally stumbled upon some dudes site where he was building a ciao like this.


Re: electric build planning...

Ѭ ɞŦЯʚOluv Ѫѫ /

Great idea. I wouldn’t be bold enough to go past bicycle wheel hubs myself and that limits what you can run.

Batteries are expensive but just find someone who vapes and steal theirs?

Re: electric build planning...

Probably Fred /

Re: electric build planning...

Re: electric build planning...


Has a 2000w-ish motor+controller setup for under $250. Documentation included

Re: electric build planning...

saw a youtube series of someone building a pack out of nissan leaf cells for a huge solar battery bank for an RV.

leaf cells are 7.6V 64Ah so 6 of em gets you into 48v range at ~$100 a pop.

Re: electric build planning...

Its lookin like LiFePO4 is going to be the battery pack. Not the best power to weight ratio, but they don't overheat and catch fire like those other ones, significantly cheaper than Samsung rare earth metal cells, I won't have to build the pack from small cells via spot welding, and they are far superior to lead+acid. Unfortunately, this means I won't be using arduino due to the battery voltage management required during discharge to avoid damaging the cell.

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