[280z1975]

Well I am now getting serious into building an electric scooter. But I wanted to get some help with some ideas on the key parts.

I have a budget of € 800 to 1000 euros (about 1200 usd to 1500 usd).

I can get a used moped/scooter here for around 150 to 250 euros. I then have this battery:

http://cgi.ebay.com/48V-20AH-LiFePO4...item3356b1f98c

which I would like to use, LIFEpo4 48v 20ah and they have been going for around 250 to 300 USD when placed on auction (which I would call thier 'market value' as opposed to the 499 most people are asking for them as buy it now items. Anywho, that would mean it would be around 350€ shipped (and some taxes added) to my door.

Now I am left with a budget of around 400 to 600 USD for the motor, controller and other parts. Which is a fair budget for what I want from the scooter. I've been looking a long time into car EV's and know what I want, but for a moped/scooter, I am not sure.

I would like a top speed of around 60kph (37mph) and the ability to cruise at 45kph for at least an hour (which I figured I could do via another thread, thanks for the help guys). So which motor and controller am I looking at.

One out of the box motor I saw was this one:
http://hobbycity.com/hobbycity/store...28eq:_70-55%29
at 150usd it's cheap and is rated to 7kw max, so it should be powerful enough, but I am just not sure. The controller to go with it is around 100 usd. So it leaves some extra cash for the other things I would need.

Also, I don't mind buying from the US as I will be there on a trip in December to visit the parents, so I can have things shipped to them. With the weak dollar, it should help me save some cash.

Let me know what parts you guys have used that worked well and what you would do in my position. Thanks for the help.

-Gregg-

[mxmtech]

The battery you have selected only puts out 20 amps at 48 volts, unless my math is wrong that means the max motor size that you should use is 960 watts. The motor you are contemplating uses 150 amps. You would need 8 of the lithium batteries to use this motor to its capacity. A 960 watt motor would use up this battery to 100% discharged in an hour which would kill the battery very quickly. If you intend to run for an hour and a half on this battery you shouldn't exceed 450 watts and that is assuming 100% efficiency from the battery.

[280z1975]

Originally Posted by mxmtech

The battery you have selected only puts out 20 amps at 48 volts, unless my math is wrong that means the max motor size that you should use is 960 watts. The motor you are contemplating uses 150 amps. You would need 8 of the lithium batteries to use this motor to its capacity. A 960 watt motor would use up this battery to 100% discharged in an hour which would kill the battery very quickly. If you intend to run for an hour and a half on this battery you shouldn't exceed 450 watts and that is assuming 100% efficiency from the battery.

As I understand it most LIFEPO4 batteries can go to 3C rate for short bursts and then remain at 1C for their stated capacity. This would give me a power of around 2880 watts for short bursts and long term constant wattage of 960 watts. These requirements should be well within the range of this motor. In the idea of my set-up, it's my batteries which may be the limiting factor (depends on the controller I choose).

http://www.diyelectriccar.com/forums...91&postcount=4

This was from a previous thread I did about range. I do believe this estimate to be true as it's about 150 to 200 watts over what it would take to move a bicycle at that speed.

That assumed, and an 80%DOD (.768kwh in the battery). I could theoretically go 1.4 hours (an hour and 20 minutes at that speed). Which is about where I would like to be (5 minutes out to the canal, 50 minutes motorpacing and then 5 minutes home). It cuts it close to my desired place range, but the jump to a 30ah battery is more than double the cost. My best thought was to just buy two of these batteries and string them together to get 40ah out of them at 48v (5,760 watts of max power, just under 3000 watts of constant speed potential). Since two of these is cheaper than one 40ah battery, plus I can charge them in the same time as the 20ah since I would have two chargers (). Then I would have around 2.8 hours of flat drive time, which is plenty to do a HARD 1.5 of motorpacing (sprints at 60kph, flat pacing at 50kph).

[Amberwolf]

You may also want to go to the Endless Sphere forum and look at Recumpence's reduction drive, designed for use with high-speed heli/RC motors like that:
http://www.endless-sphere.com/forums...php?f=1&t=6163
Might also have more in this thread:
http://www.endless-sphere.com/forums...hp?f=28&t=7180

There's also this one he did for Y-pedal:
http://www.endless-sphere.com/forums...hp?f=28&t=9342

Also read up on the Vpower stuff while you're there. There have been good and bad reports about them, in various threads.

This thread may also have information useful to you:
http://www.endless-sphere.com/forums...hp?f=28&t=4625
and this:
http://www.endless-sphere.com/forums...php?f=2&t=5594

[280z1975]

Originally Posted by Amberwolf

You may also want to go to the Endless Sphere forum and look at Recumpence's reduction drive, designed for use with high-speed heli/RC motors like that:
http://www.endless-sphere.com/forums...php?f=1&t=6163
Might also have more in this thread:
http://www.endless-sphere.com/forums...hp?f=28&t=7180

There's also this one he did for Y-pedal:
http://www.endless-sphere.com/forums...hp?f=28&t=9342

Also read up on the Vpower stuff while you're there. There have been good and bad reports about them, in various threads.

This thread may also have information useful to you:
http://www.endless-sphere.com/forums...hp?f=28&t=4625
and this:
http://www.endless-sphere.com/forums...php?f=2&t=5594

Thanks for the links, will get after then when I get back from work.

[mxmtech]

960 watts times 1.6 hours equals 32 AH

[mxmtech]

I would MUCH rather replace my motor than my batteries. My little 450 watt motor will operate at 720 watts if I push it hard, but my batteries can handle it. The motor you're looking at will accept a demand of 11.2 KW and the batteries are not up to it. I have about $600 invested in my batteries but I figure I could replace the motor for $60. Plus I can smell the motor when I start cooking it and I can stop.