How to Build an E-Bike: The Motor/Controller

 

 Intro

So you’ve seen some e-bikes going down the road and they look like so much fun. OR you’ve been reading about how much better for the environment ebikes/trikes are and you want to jump on this band wagon. OR any one of a million other reasons, but the point is- you have fallen in love with electric bikes and you want to build your own.

There’s a lot of reasons to build your own instead of buying an ebike off of Amazon. My big two reasons were I absolutely loathe the fat tires aesthetically, and in the case of my ebike, I wanted full suspension ( speed bumps at 30 mph one a fixed frame- you feel it in your spine). So while building my third ebike (actually a trike this time), I took some pictures an am writing a blog post.

Also- at Electric Elk we strongly believe in safety, and I’ll also be putting a full electrical kit on it, but that will be a future post. This post will be about hooking up the motor, battery, and other components on a new model we will be calling the X-3-1000-a.

For this trike, I bought a 1000 watt front wheel drive kit on Amazon as well as a forty amp hour LiFePo-4 battery, and mounted it all to a trike I also found on Amazon. The purpose for this vehicle is to run to the suburbs and back with a friend to visit another friend.  Note, the 1000w motor technically makes this trike not street legal under Chicago’s 3 class system. If you live under a 3 class ebike regime, and you care, you should probably order something smaller like a 250 watt or at most a 750 watt motor/hub. 

Note, at the time of this writing- I am not an Amazon Affiliate and get no kickbacks from Amazon if you buy any of this stuff. 

Step 1: Get a Donor

So the first step of this project was to build the trike- it’s about an afternoon project for someone with not much mechanical back ground or 90 minutes for someone with experience puting bikes together. I though about making a blog post for that too but I forgot to take pictures.

Step 2: Front Wheel

The next step is to open up your package of the motor/hub/controller. The first thing I like to do it swap out the front wheel- note, I did the front wheel on this trike because it simplifies a lot of things- especially on trikes with dual rear wheels. Something to note, the e-trike is going to have large lug nuts, mine was 22mm so be prepared by either having a large array of metric wrenches or some time and plans to make a couple of trips to the hardware store for tools.

22mm Wrench to Install My Lug Nuts

After I secure the front wheel, I normally will use some electrical tape to secure the wires along the fork to keep them out of my way and from getting caught up in the wheel.

Step 3: Throttle and Brake Levers

The next step (in my approach, but these aren’t cumulative) is to pull the left handle bar and install the sensored brake handles and throttle. The sensored brake handles cut power to the motor in the original setup- but in out setup will also be used to trigger the brake lights.


The tools required for this step are allen wrenches, so once again- make sure you have a nice set of metric allen wrenches before starting or make another run to the hardware store.

Step 4: Control Box

The next thing I had to install was the control box. I put it here at first but I’m going to build a new box for the battery and control box, so don’t take my mounting as gospel. But you do want to put it somewhere secure and relatively dry, though they should be a bit water resistant.

Step 5: Connect Wires

Now, as simple as this all seems, you’re almost done! Just need to hook up and clean up the wires. This motor/controller set I bought has some absurdly nonsensical hook ups, which I don’t care for and very well may swap out too, but all the other kits I’ve had all the pieces had pigtails and nothing like this. At any rate, the pigtails should all click together pretty self explanatory, and hopefully you don’t have some mess like this. 

Step 6: Cleanup Wires

Now, you technically have an ebike- you could hook up the battery and it will go, but you also still have a borderline dangerous mess of wires. So let’s clean those up with some flex conduit, also available on Amazon, or from any auto parts store.

This makes the job look much cleaner and keeps wires from getting caught up in your  pedals or anything else. Don’t be parsimonious with the electrical tape here as well.

So there you have it- that’s how you build an ebike/trike. In future posts I plan on showing the new battery cage, and more importantly, how to make this rig safe with automotive turn signals, running lights, and horn.

Thanks for reading!