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Electric Motorcycles

The confluence of Elec-Trac and BMW
 

Electric BMW R75/7

I've been kicking around the idea of building an electric motorcycle (EM) for several years. I got into Elec-Tracs to get my feet wet on EVs. I hoped to build an EM based on a BMW and have been doing a low level search. I guess this is going to be a low-tech blog.....
 
 

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Donor Bike

Jan 2008
 
A friend from the local BMW Vintage group came though with a great donor; A '77 R75/7 that he wanted the motor and transmission out of. It's in real good shape mechanically so I won't have to mess with the chassis too much.
 
 
 
 
 
 
 
 
 

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HiTorque motor, chain drive

 
May 2009
 
I went through several iterations over the past year and here I am in spring 2009. I have a 7" HiTorque motor and added a 2:1 chain drive reduction, as direct drive was just too geared too low (3.37:1 rear end). Controller is an Alltrax 4845. This setup works well; good pep running around the yarrd. This shows my rough setup for testing with 3 12V Hawker SBS60 batteries.
 
 
 
 
 
 

AXE monitor software and manual

In order to get data from my test setup I wrote code for my Palm PDA to display and log the data availble from the Alltrax.

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AXE monitor on Palm Vx

Electric Mini-Bike 

Saab, Elec-Trak, Slash 2, etc