Custom Sport Scooter Project

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Scottydog
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Custom Sport Scooter Project

Post by Scottydog » May 15, 2014 11:10 am

Hello Guys,

So I am new here having joined maybe 6 months back. I'm a two stroke fanatic who has decided to dabble into the electric world.

I have a project which I originally penned about 6 years ago. The bike is a Derbi GP1 scooter which houses the engine within the frame. When I saw this bike I thought it had a huge potential as an electric scooter, but put off when I realized that due to battery and motor options would be difficult to package. I put the idea on the back burner and forgot about it until recently.

When I noticed that there were better battery options and various improved choices regarding motors I decided now was the right time to start up the project. So first thing was to source a bike and have shipped over 3000 miles at considerable expense to my location. I had never seen one so based on photos on the internet guesstimated the chassis potential for battery capacity.

I now have not one but two of these bikes in my possession with which to strip and work on the packaging of the various electrical components. Last week I discovered my guesstimated battery layout worked out (just) bring more excitement and confidence. As shipping/taxes are expensive I have to take a cautious approach to the design to avoid expensive mistakes.

At the moment I am using two Emoto G5 scooters as a reference which ironically mimic the concept of the Derbi scooter I had in mind, but they are not of the same high quality. The first stage of the plan is to build the scooter using the full componentry of the G5 for proof of concept. Once this is done I will purchase the higher spec components to build the final design.

I will write more about this later.

Scottydog
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Re: Custom Sport Scooter Project

Post by Scottydog » May 15, 2014 12:59 pm

So this is a mockup of the idea I had back in 2008/2009 for the bike. I wanted to use the existing chain drive as at the time wide, large diameter hub drive motors for scooters did not exist. I was planning to use 40Ah Thundersky lithium batteries with a Perm PMG 132. I think during the working out of battery configuration and motor sizing I realized it could be a tough setup to package. Not wanting to risk ordering the components and finding out it would not be feasible I put the project off. Will post a photo once I figure out how to do so with Flickr.

Image

Scottydog
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Re: Custom Sport Scooter Project

Post by Scottydog » May 15, 2014 2:01 pm

So when I saw the Chinese Emoto G5 which was very similar to my idea the 13" hub motor looked perfect for my project! I later saw the higher specification ZEV scooters and they were a source of inspiration for higher quality components!

Image

Scottydog
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Re: Custom Sport Scooter Project

Post by Scottydog » May 15, 2014 2:28 pm

So this is where I am now! I have the scooters and removed the engine. I used a set of 60Ah Elite Power cells to test out the fitment on the scooter, which let me understand how their 40Ah cells will work. It worked out perfect and will allow me to use the 28 cells that I planned to use. The idea is to use the G5 electrics and motor to help me understand building my first scooter.

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When I go to build the real design it will be good to get thoughts and ideas from forum members. My first quandary is choosing the idea hub motor! The Chinese motors while easy to use require making adaptor inserts for the rear swing arm. It is not a huge deal, but does mean the rear is a smaller size than the front and adds a few inches to the swing arm length. The Enertrac hub motor is therefore a more attractive option, but there could be some challenges regarding overall gearing with the 602 motor on a 14" wheel and whether such a small rim can be fitted to the hub. I am crossing my fingers in that it can be done, as I think the overall performance would be perfect! :D

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Dauntless
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Re: Custom Sport Scooter Project

Post by Dauntless » May 15, 2014 11:41 pm

http://www.saferwholesale.com/125cc-Pho ... lb4%29.htm

Something like this comes with a swingarm.
Any sufficiently advanced technology is INDISTINGUISHABLE FROM MAGIC!
- Arthur C. Clarke

John in CR
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Re: Custom Sport Scooter Project

Post by John in CR » May 18, 2014 6:13 pm

Unless the spoke flanges are unusually far apart on the Enertrak motor, I don't see any reason it can't be laced into the right 14" moto rim. I got some motors of similar diameter back in 2008 that came with 14" rims and short spokes to match. The spokes are at significant angles that the rim holes are designed to accept, so it works fine with single cross lacing. Just be sure not to use radial lacing, because there's a common misconception that radial is ok, but it's not ok in a driven wheel. If you want high speed you'll need to go to pretty high voltage with the Enertrak in a small wheel, but the motor will love being in the small wheel.

Scottydog
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Re: Custom Sport Scooter Project

Post by Scottydog » May 19, 2014 6:30 pm

Hi John,

cheers for your reply. Yeah I have to think for a 50mph - 65mph range depending on voltage the motor will be very grunty I imagine!

I had only just remembered your hubmonster and emailed you with thoughts on that motor also. Admittedly I liked the 10rpm per volt on the Enertrac.

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Re: Custom Sport Scooter Project

Post by John in CR » May 21, 2014 3:58 pm

Yeah, but you've built some beautiful gasser stuff. I'd rather see you start with something featherweight, ie a simple build starting with a bicycle, so you can appreciate the performance. Then armed with that appreciation you put your heart into it. Starting with something as heavy as planned, you have to go big to have the power to weight I believe electrics deserve....actually torque-to-weight, because mid power (10-15kw peak) can be eye opening as long as it's not geared for speed too high, and the weight isn't too high. Excess power and excess torque is what you want, because then incredible performance is possible without system stress, and if nothing is stressed they approach 0 maintenance with absolute reliability.

Scottydog
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Re: Custom Sport Scooter Project

Post by Scottydog » May 22, 2014 2:21 pm

Hey John, cheers about the gasser stuff!

I had thought about the lightweight bicycle option, the trouble is here something like that would have to be registered. And because it is bicycle derived I doubt it would ever be allowed. But the other factor is I wanted to build something that passes as a "normal" gasser bike, with helmet storage etc. Because I am new at this, want to try keep the whole concept very plug and play. So no fancy homemade battery packs or time spend playing with halls, waveforms etc!

Still playing with the spreadsheets the bike would not be so bad. Weight would be 264lbs + 160lb for me which compared to some of the commercial EV bikes is pretty good. Time will tell though once it is built!

Currently I am making the carbon battery tray.

John in CR
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Re: Custom Sport Scooter Project

Post by John in CR » May 24, 2014 2:31 am

Scottydog wrote:Currently I am making the carbon battery tray.
Ever since I saw this frame hidden under the plastic of a big Zev scooter. All I can think of for a scooter build is doing a carbon tub and getting rid of all that steel along with the battery box not included yet. Of course the rear would taper to a proper aerodynamic point.
Zev scooter frame jpg.JPG
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Get rid of all that steel and weight and welding and for low weight get that massive battery space.

At least you're starting with an attractive scoot, so you'll end up with a very practical and nice looking EV to use. If you get anywhere near decent performance, I can pretty much guarantee that within a week of riding it, you'll have plans for the next much lighter build under way. Have you seen Audi's electric bike? You have the build skills, so something like that, but a bit fuller for more batts and more power and torque. Add enough lighting and brakes to pass inspection, and you'll have an ear-to-ear smile with a perfect vehicle for such a small island.

BTW, are the authorities really uptight about the rules, so you couldn't get away with a high power ebike as long as you don't do stupid stuff in front of them? I can't imagine being on a small island without a relaxed attitude as long as you aren't putting others at risk.

Scottydog
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Re: Custom Sport Scooter Project

Post by Scottydog » May 24, 2014 12:28 pm

Hey John,

yeah for sure I was thinking to build a carbon tub chassis, but when I saw the Derbi figured it would be a much easier route. I'll have to look up the Audi bike see what that one is like.

Was talking to my bike shop buddy, he sells the specialized electric assist bike and we were wondering how higher powered ones would be viewed legally. I think it's a grey area, but very likely one that won't last for long once the commercial E-bike thing takes off!

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MitchJi
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Re: Custom Sport Scooter Project

Post by MitchJi » May 25, 2014 4:38 pm

Hi

The best bang for the buck large format lithium cells (30 Ah) are used Nissan Leaf modules (2s2p) available for about $140 shipped. Check the links in my signature for more information.
Best Wishes!

Mitch


The best quality batteries and lowest priced batteries for DIY EV's are tier 1 OEM Quality Cells from salvaged (wrecked) EV packs. Two examples are Chevy Volt and Nissan Leaf packs.

Nissan Leaf Module specs are here
Chevy Volt Pack Info - Salvage 16kwh Packs Under $2k here
The cells are rated conservatively by GM at 7.8C, Yabert's tests of Volt packs on the DiyEv car forum suggest a higher C rate, 15+ C!.

$1,400 plus $360 freight. Still over $1k less than new lead!

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Re: Custom Sport Scooter Project

Post by Tek » Jun 03, 2014 1:11 pm

Run the Chain-drive and some sort of BLDC Liquid-cooled motor. That Derbi is pretty much the kind of the Scooter designs...roll with that. :mrgreen:

Scottydog
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Re: Custom Sport Scooter Project

Post by Scottydog » Jun 04, 2014 5:51 am

Tek wrote:Run the Chain-drive and some sort of BLDC Liquid-cooled motor. That Derbi is pretty much the kind of the Scooter designs...roll with that. :mrgreen:
Oh yeah for sure you know that is happening! I have 2 of the chassis and that is exactly the plan for the second one. But being new to this electric stuff, want to go the softer route first! :D

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MitchJi
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Re: Custom Sport Scooter Project

Post by MitchJi » Jun 05, 2014 6:58 pm

Scottydog wrote:Hey John,

yeah for sure I was thinking to build a carbon tub chassis, but when I saw the Derbi figured it would be a much easier route. I'll have to look up the Audi bike see what that one is like.
http://www.electricbike.com/audi-ebike/
Best Wishes!

Mitch


The best quality batteries and lowest priced batteries for DIY EV's are tier 1 OEM Quality Cells from salvaged (wrecked) EV packs. Two examples are Chevy Volt and Nissan Leaf packs.

Nissan Leaf Module specs are here
Chevy Volt Pack Info - Salvage 16kwh Packs Under $2k here
The cells are rated conservatively by GM at 7.8C, Yabert's tests of Volt packs on the DiyEv car forum suggest a higher C rate, 15+ C!.

$1,400 plus $360 freight. Still over $1k less than new lead!

Scottydog
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Re: Custom Sport Scooter Project

Post by Scottydog » Jun 06, 2014 7:51 am

I was having something similar to this in mind. Basically an inverted T or upright U design.

Image

Scottydog
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Re: Custom Sport Scooter Project

Post by Scottydog » Feb 08, 2015 9:01 pm

So been doing a bit more over the last few months when I get the time. Started by making the carbon battery tray which then would allow for the GBS style batteries to fit nicely. I did get side tracked not soon after as we got hit not by one, but two hurricanes within a week. I was off island but the bikes got blown over and the Kelly controller fried by water damage! :(

But I finally got back on track so hope I can get it in a riding state soon!
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Scottydog
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Re: Custom Sport Scooter Project

Post by Scottydog » Feb 09, 2015 10:26 am

So with the battery tray sorted I kept in mind how I would fit a hub wheel to the bike. I wanted to use one like the Enertrac one with the removable axle but I didn't get much response on figuring out how to make it work for a 14" wheel. So abandoned that route and stuck to the 13" Chinese hub motor option.

As I didn't want to permanently alter the swingarm on the bike and because the shaft length on the Chinese hub motor is limited, the best option was to make a insert for the swingarm. It would add about 2" to the overall length, but this wouldn't matter and once things are adjusted would probably not be noticed much.
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Scottydog
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Re: Custom Sport Scooter Project

Post by Scottydog » Feb 09, 2015 10:45 am

Style of fitment to be used. Idea is to design a system with a similar layout to be inserted inside the hollow box section of the swingarm.
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Scottydog
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Re: Custom Sport Scooter Project

Post by Scottydog » Feb 16, 2015 5:39 am

So time to design the rear hub mounting system. The idea is to go with a method that doesn't permanently modify the swingarm. So the best option was to design an insert system. It will lengthen the swingarm by 2" but in the scheme of things this isn't an issue really. The 125cc version of the Derbi has a longer wheelbase by this distance already so this would work out quite similar.

This initial design is based on CNC machining out of a stainless steel. But there were some challenges with this design, so I designed to go with a different design which would hopefully be a lower cost and easier to fit if tolerances were slightly off.
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4LivesPerGallon
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Re: Custom Sport Scooter Project

Post by 4LivesPerGallon » Jul 24, 2015 11:21 am

Nice project. Good luck. Let us know about your success, esp. with the battery balancing. Cheers!

Scottydog
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Re: Custom Sport Scooter Project

Post by Scottydog » Jul 25, 2015 9:14 pm

Hey no worries, I realised I've done a bit since my last posting a while back! So I went with a simpler motor mounting design which could be done completely by laser machining and so cut costs. Once I got the parts back I test fitted everything and so looks like it's all good! :D
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Scottydog
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Re: Custom Sport Scooter Project

Post by Scottydog » Jul 25, 2015 9:25 pm

With motor mounts installed into swingarm and wheel fitted.
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Scottydog
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Re: Custom Sport Scooter Project

Post by Scottydog » Jul 25, 2015 9:31 pm

Caliper installed
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4LivesPerGallon
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Battery cost only $140 shipped????

Post by 4LivesPerGallon » Jul 27, 2015 1:24 pm

Could you please elucidate how to get a Lithium pack for $140, thanks.

In the meantime, my jaw is on the floor...

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