Jul 20, 2013

DIY Electric Bike - Building the Ultimate Commuter [UPDATED]

5/22/2013 - Where to Start

Between work, home life, and responsibilities, my personal time consists of my drive to work and my drive home. An 11 mile drive from work to home takes me 40 minutes on some days--that's California Bay Area traffic for you. I want to turn that time into something productive where I can bike to work to enjoy the outdoors, get exercise, and save money.

Production eBike vs DIY build
When I think of an eBike, I see myself flying up hills, feeling the adrenaline rush of torque, and the wind howling in my ears. Top speed is not so important for me but how fast I get to 20mph is. My time is limited. I like learning new things, but then again, I cannot dedicate time to experiment. Therefore, I want a bike that's quick to assemble, parts I can replace, and teaches me something while I build it. 

Comparing the production ebikes like the Stromer ST1, BH Emotion Neo Jumper, and a2b Metro/Octave resulted in prices around $4,000 with features like purpose built frames, high quality components, and pedal assist. From my reading, the power ranged from 250w-500w. The good thing about production bikes are that they're ready to ride, have a warranty, and can be well designed. The bad thing though is that they use proprietary technology, so if you have issues, you'll have to go back to the manufacturer. Also, upgrading the ebike takes a lot effort and time.

My plan is to purchase a bike and an eBike kit from a USA distributor, assemble, and document the challenges and fun of commuting via an eBike to work. I like the idea that I can replace parts if they break, and the power per dollar is better in an eBike kit when compared to a production ebike.

Stromer ST1

BH Emotion Neo Jumper

a2b Metro/Octave
The $10,000 Stealth Bomber

5/23/2013 - Purchased the bike

'06 Marin Nail Trail

Looking through Craigslist ads was fun. Imagine the possibilities. I started my search dead set on getting a downhill race bike because I liked the full suspension and loved the look of the front forks. However, after thinking about the initial cost, maintenance for the suspension, and battery placement, I ended up going with a '06 Marin Nail Trail hardtail mountain bike. I figure the hardtail mtb triangle is plenty big for the battery, and the price of the bike will provide flexibility when I choose the motor kit and battery.

Next on my list will be a full tune up for the bike, and a possible brake upgrade.

5/24/2013 - Purchase rear brake

$81.45 Picked up a Hayes Stroker Trail hydraulic brake to replace the aging rear Hayes Nine brake. http://ebikestop.com

6/6/2013 - Accessories installation

An old bell ringer
Stroker trail rear hydraulic brake (front brakes were stroker trail brakes when I purchased the bike)

Giro Remedy 2013 Full Face Helmet made from fiber glass. Check out the unboxing:

6/24/2013 - 48V 10AH LiMnCO2 battery fitment

My electricrider.com battery arrived today. Before purchasing the battery, I used the spec off of electricrider's website to estimate the fitment in the triangle. Luckily, it's a perfect fit with some extra space for some padding. Now I can move forward and pick up a triangle battery bag to house the battery.

Top view of the 48V 10AH electricrider.com battery
Side view of the 48V 10AH electricrider.com battery

6/26/13 - Battery Box Enclosure

I used a 3-5/8 in. x 10 ft. 25-Gauge Galvanized Steel Wall Framing Stud and stainless steel U bolts to build the battery enclosure. The parts were picked up from Home Depot. 

Metal shears

ElectricRider.com 48V 10AH LiMnCO2 battery fitment

Cut the metal with some metal sheers
Cut an aluminum 90 degree bar to use as an edge to bend the metal
Bent into shape the battery enclosure
Test fitted the enclosure
Drilled holes for the U bolts

6/29/13 - Installed the kit

Parts parts parts
Test fitted the controller--this location ended up hitting my legs when pedaling 
Kit installed

7/2/13 - Rear rack & fenders

SKS Grand MOM and Grand DAD fenders
Blackburn SPX-1 Ultimate Seatpost Rack

Used wire loom to hide the wiring, and routed the wires to the seatpost rack

7/6/13 - First ride

The ride was comfortable, destroyed the hills, tons of torque, and was a blast to ride. It's going to be my daily commuter going to and from work. 

Felt like I was going warp speed when I hit the top speed--definitely did not expect that. 

Please excuse the poor quality Bluetooth audio. My helmet cam failed, but the GoPro kept on truckin.

Marin Nail Trail 26" Hardtail MTB
48V LiMnCO2 10AH electricrider.com battery pack
4840 26" Rear electricrider.com brute kit W/LCD display
Twist grip throttle
Schwalbe 2.15" Marathon Mondial tires
SKS Grand MOM and Grand DAD fenders
Blackburn SPX-1 Ultimate Seatpost Rack

7/7/13 - Added CRG mirror and Crampbuster

Crystalyte APM display - Battery meter, Speed, Efficiency, Torque, RPM and more

7/19/13 - Pletscher Double Kickstand

Added a much needed kickstand. The great thing about the Pletscher double kickstand is that it folds up into a single kickstand making it compact and looking slick.

8/24/2013 - Carbon Fiber battery reinforcement

On my setup, the battery's weight sits on one of the corners in the battery enclosure. My concern was the weight would put pressure on the battery cell, and riding over bumps would cause the cell to eventually get crushed.

I went ahead and added a single layer of 5.8oz carbon fiber and epoxied it to stiffen up the two bottom corners.

The batter is now solid.


Useful eBike Links


Quantification of Car vs. eBike



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