DIY Razor electric scooter?

[jasonck08]

So for a while, I've been wanting to DIY an electric razor style scooter. My goal of this project would be to make an affordable, extremely light and compact scooter with decent performance for its size.

I've worked a little bit with electronics, but have never attempted anything of this type.

To make it light and compact I'm trying to use as many RC parts as possible.

Parts list:

-Razor Pro scooter (about $50 and can handle a full adult easily)
-Turnigy 5AH 18.5v Li-po battery (~93 Whr's)
-Turnigy 900W electric motor (more power then I need. I plan to run it at 250-400 watts full throttle).

So now I'm not sure what else I should buy. I'm not very familiar with speed controllers and throttle controllers. I see some 250 and 350W electric scooter speed controllers on eBay, but I'm not sure exactly how they wire up.

Any tips or advice would be appreciated. And just so you know, I'm fully aware that with the battery and motor that I won't get very much range. 4 miles max according to my calculations. I could always rig up a second battery to get up to 8 miles of range. This project is meant to be fun, not necessarily practical for day to day use.

[jasonck08]

Really... no posts? No one that has built an EV can chime in and advise me?

[brucey]

Why not just buy a ready made scooter and hop it up a bit? I had a Schwinn Stealth I ran at 2000 watts without any problem. Avoid the direct drive on those though, they're more trouble than its worth.

[jasonck08]

Originally Posted by brucey

Why not just buy a ready made scooter and hop it up a bit? I had a Schwinn Stealth I ran at 2000 watts without any problem. Avoid the direct drive on those though, they're more trouble than its worth.

1) Because it doesn't weigh 15lbs and fit into a backpack.

2) Because I can't build it myself.

The whole point of this project would be to gain experience about building an EV from scratch (a darn small one). Eventually I want to attemt an EV motorcycle and or car.

[Ryland]

What speed does that motor run at? lug it down to much and it's going to draw more amps then it is designed for and it will burn up, you might be better off just using that motor with a prop to push you as the gear box might be the largest cost of the project.

[jasonck08]

I was planning on rigging things up like this:

http://www.youtube.com/watch?v=yhTT3H-iaEM

The motor is rated at 500kv. If I power it with an 18.5v Li-po pack, then the motor should spin at ~9,000 RPM's.

I'm not going to use a gear box. Just a small chain or belt drive system. Not sure about the gearing and stuff like that...

A 1:10 gear ratio - 900 RPM would give a maximum speed of ~10mph.
A 1:5 gear ratio - 1,800 RPM would give a maxium speed of ~20mph.

So I'd probably gear it at about a 1:4 ratio or so. That way I could keep the motors RPM's down while cruzing at 10-15mph.

Thoughts?

[Ryland]

if you put to much of a load on that motor it is going to burn up, you want it to spin fast while it is working, it's designed to work with almost no load on start up and the load increases as the speed increases, so unless you plan to kick the scooter up to 15mph...
I would gear it to 8-10ph top speed, if it sees happy then re-gear it to go faster.

[NeilBlanchard]

Where would you put your back foot?

[luvit]

i would do it. how much could that motor cost? if it burns up then i use a different one.
kick up the scooter to 7mph may not be too hard.
wear a helmet, in-case you can get to 10mph..