# Eric's EV Moped



## eric-ev (Apr 28, 2009)

UPDATE: bike done


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## Jozzer (Mar 29, 2009)

Nice project, looking forward to seeing it unfold.
Are you absolutely sure though that it can be called a bicycle? In most places of the world electric bikes are limitied to less than 1KW of power (here in UK it is 250w!)

Steve


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## eric-ev (Apr 28, 2009)

Update from the weekend - The battery rack is welded in and looks BEAUTIFUL! The only things I'm waiting on now is my rear sprocket (it'll be in Monday), and the battery tie-down straps (Thursday). I may be riding as soon as Tuesday if I can find something else to hold the batteries in temporarily. I still need to mount some electronics and do some wiring so Tuesday is the earliest, for sure!

Thanks for the words of encouragement!
~E


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## frodus (Apr 12, 2008)

it may meet the definition of a bicycle.....but as I stated on elmoto....(only reposting for others to see). If you go over 25mph, you have to have a valid drivers license..... thats the hairy part.

According to Indiana Code the following restrictions apply to a motorized bicycle: 
1. It may not be operated by a person less than fifteen (15) years of age. 
2. By a person who has not obtained an Indiana Identification Card or Driver’s License
3. On an interstate highway or a *sidewalk*
4. At a speed greater than twenty-five (25) miles per hour.


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## eric-ev (Apr 28, 2009)

Update - batteries are in and are being wired up! I have the 72v string running and ready to mount controller, etc. The new paint looks great! The chain is on now too. I ran into a problem after mounting the batteries - the front end is too heavy now! Either the shocks are old or need refilled, because the front wheel is sitting on the battery rack when I drop the center stand.  I'll try refilling tonight and see how it does. Pictures forthcoming!!



Yes, nobody would be interested in driving on the sidewalk!


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## frodus (Apr 12, 2008)

Just gear it right so 25mph doesn't use a lot of current.....sure it'd decrease top end, but i don't know if you're much worried about going 70mph at this point, are you?

Of course, its only a quick front sprocket change with some cheap machine chain and you're at the drag strip.


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## eric-ev (Apr 28, 2009)

Right on Frodus. I'm starting with the highest ratio I could achieve - 10 front, 60 back. The chain just barely clears the swingarm so a taller back would not work. I do have the 15 front sprocket so the swap is not a big deal to get ~100mph top speed, I may not even need to change chains as there is plenty of adjustment on the back.

As it is with a 6:1 ratio I'm at 82% effeciency (max) at 38mph, I'll redline at 61, and be at 72% effeciency at 25mph.

The first road test will be this week God willing, so updates are to come!


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## frodus (Apr 12, 2008)

don't use a 10.... its way too small of a bend radius, you'll be WAY more likely to bind, and it'l wear the chain very quickly and be very loud. I'd go up to 11/66 or so if you want a 6:1.... sure its only 1 tooth, but it makes a world of difference (personal experience). I've tested 10/11/12/13 on mine, i'm using a 12 now.

Also, I doubt you'll get to 100mph with that motor... i don't think it'l spin that high or provide enough HP to get to that speed.....but I could be wrong.


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## Jozzer (Mar 29, 2009)

I'd go further, I've experimented with 10 to 17 teeth front sprockets, and will now not use less than a 13 up front. If I were you and wanted high torque/low speed I'd look at a gear reducing jackshaft to get it right.

Anything less than 13 will make a real mess of your chain (like less than 1000 miles before replacing chain and front sprocket) and make a racket like you wouldnt believe! A small sprocket is in effect a polygon not a circle, a 10 will feel like you have a square one (or a badly balanced motor). It will increase wear also on the motors bearings..


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## eric-ev (Apr 28, 2009)

Well good thing I got the larger front sprockets then! Thanks for the heads up guys, I'll start with the 10 and if it doesn't look kosher I'll move up. I can't do a larger rear without more modifications or an idler, but if it comes to that I guess it'll have to happen. 

Definately no room to do a jackshaft without SIGNIFICANT customization and cost. Great idea, but its not for me.


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