Ebike Wiring…Defining the Rats-Nest

Editor note: Part 2 of a 4 part series on the wiring of DIY ebikes

Make no mistake about it…there is no great deal of expertise in building a drive system for an electric bike. It is not rocket science….it is not even as hard as tuning a car science. DIY ebikes have an array of wires that can quickly and often times turn into a rats-nest if the builder is not thoughtful. Wires are a messy problem. Where as the rest of the technology industry is going wireless, it seems that ebikes have just as many wires as ever. I see it I as the biggest drawbacks to DIY ebike compared to a commercially available ebike. Commercial ebikes keep getting better…DIY components have pretty much stayed the same, with only one or two exceptions.

If you are thinking about building an electric bike, you are going to have to deal with putting together some kind of wiring mess, since as of 2015, DIY components are pretty much straight out of China, and…China couldn’t care less about how cluttered  or unattractive your ebike looks.


Example of how a commercial bike handles wiring:

Lets take a look at typical commercial ebike, and see the one sure way a commercial ebike can put a DIY bike to shame:


The Juiced Rider is a great example of a nicely built commercially built electric bike (one of my favorites) with only a few visible wires.   Notice the lack of handlebar clutter, which you can think of as a riders feng shui.

But lets just focus on how that nitty griddy of how that ultra neat handlebar wiring is planned out and finally made. First it starts out a schematic:

ODK V3 (Dream Cable) copy

Here is the schematic of how the front connectors fork out from one connection coming from controller:



According to Tora, owner of Juiced Riders who is one of the few ebike manufacturers who is open about the way he sources in China:

“It is really hard to make the cable as we have to order both sides of the cables at the exact length from the cable supplier. Check and separate them when they come in. Then send each piece to the different suppliers, motor, controller, display, throttle, brake so they can ingrate them into the component before they send them back. Then hope everything works out when it arrives! It could take several months.
To get the clean look, we have to align them first on a wiring harness board before going onto the bike. We go through great “lengths” to make the wires look nice. By far it is the slowest process of the assembly. “

IMG_1918 IMG_1767 IMG_1765
So you can start to see the advantage a commercial ebike has when it comes to wiring. Because he is making hundreds or thousands of ebikes at  a time, he has the opportunity to thoroughly plan the wiring set up, and then have low paid chinese workers put it all together…..this is the most difficult part of the assembly process for I suspect most electric bikes.

Through out the commercial ebike industry, quick connectors are becoming a hot item. Check out the latest generation with steel connectors:


QR connectors


Quick connectors  make replacing the hub motor or controller or throttle as simple as disconnecting one quick connect which is  way less complicated because there fewer individual wires.

Much of this is possible because most commercial bikes are low-power and can get by on thin-gauge wires. Also, because commercial ebikes are designed with 3 components selected to work with each other, it is really possible to have super tidy wiring solutions, with no extra wires protruding out of the controller.

Its a good thing that American Ebike makers are demanding china to provide them quick connects…it would be hard to sell a $3,000 commercial ebike to a common consumer it if had a controller that looks like the one below…a typical DIY ebike controller:


The Disadvantage of a home ebike builder:

Home builders of course do not have access to low price China workers to build there controllers for them.   In general the products home builders have to work with tend to be too wirey (we will break it down later)  Plus making a clean set up with wires hidden and shortened to just the right length is one of the most difficult tasks of installing a hub motor drive system on a bike .  Most DIY ebikers are anxious to get their bike running (for good reason) and will just quickly put it together and pay not much attention to the wires or how messy their contraption can look.  Duct tape, zip ties,  sizzling hot soldering irons, and even bungee chords are  all friends to the ebike builder.

Also home builders tend to be like a ham radio operator, dungeons and dragons players…that type of guy who does not mind sitting around in the garage with a solder iron in hand, smoking the fattest wire he can find. Most home builders i know spend more time building than they do riding.

That is why Chinese components and many DIY’s are a good match…China does not seem to mind creating ebike devices that have an exorbitant  amount of wiring and mismatched cheap cheesy connectors that require the ebike geek to unravel, figure out, and solder. I am one of the few people I know who does not know how to Solder, and do not count soldering as one of the skills I want to pick up.

Fast or Tidy? Think fast…

hub motor kit

There is a big separation in thinking between the leaders of the DIY scene, and what is actually selling in the real world. For example…the best selling ebike kits in the United States are NOT the most powerful ebike kits (so powerful that they can send you 40-50 MPH down your block on your $200 Walmart bike), nor are they the cheapest kits. The kits that seem to be selling the best are kits that are easy to connect such as the bionx kit with the motor and controller built into hub (fewer wires) and other kits which are overpriced Chinese kits with good support, clean websites, and quick connectors. These kits are easy to install, and its easier to hide the integrated wiring system. Also, when you’re done you don’t have a bunch of loose bundles of wires protruding from your controller, for features you will never use. And if you’re lucky, your ebike will look just like a bicycle.

PLEASE!!!    Look at this Ebike builders Inspiring Pics for a breath of fresh air before we continue with wiring headache discussion 


What Chinese Function All American Ebike Builders Should Refuse:

Cruise control!   Cruise control on an ebike is ugly and wirey…and the idea that you are going to ride a powered bicyle and you dont want to get your wrist or thumb tired pushing on that throttle is pathetic.  Lets ban it!!!

What component some genius Western Engineer should bring to market:

A proper throttle.  All we have to choose from currently is chinese junk. (more on throttles later).

Why Wires Suck


Where the rest of the world is going wireless, the DIY ebike world is stuck in the wire age. The multitudes of wires in a home-built kit is the biggest drawback I see to building your own electric bike. Why?

  • Wires are ugly
  • Wires are very un-bicycle like
  • wires make an ebike less stealthy
  • Wires are hard to install…a typical hub motor installation takes 12 wires that need to soldered
  • Wires make troubleshooting an ebike extremely  difficult
  • wires make interchanging ebike components difficult unless you enjoy soldering


Ebike Hub Motors – Spinning Magnets Wound With Wires



Most ebike motors are brushless, and require the following connections to operate.

Hall Sensor wires – 5 small wires that communicate with the controller on the timing of the motor. This enables a smoother and more efficient operation for brushless motors. The soldered connections can melt if they are too thin for power you are running (Hall wires carry a low current, but they are next to the high-current “hot” motor-phase wires).

Lead wires –  3 motor phase wires…this is how your motor gets it power…the thicker the better if you want to go high power…these can get hot if too thin, and maybe even melt.

Solutions for less wires?

One of the largest producers of ebike kits is BionX (read review), who have installed the controller inside the hub motor which greatly reduces the number of wires. Many people complain that this makes the Bionx harder to upgrade, but the BionX is a really sweet solution, given that it has half the wires of most kits:


Another kit that has a super quiet sine wave controller installed and is considerably faster than the bionx is the Golden Motor Pie4.

Numerous  kit manufacturers offer their hub-motors with well-integrated quick-connects like found on commercial ebikes. It is highly recommended you buy a kit with quick-connects if you are not into soldering.

You could run without hall sensors, which would mean less wires, but the compromise is…the motor can be a bit more jittery at start up. Some DIY Ebikers run without hall wires, not only to reduce wire clutter, but also to make their ebike more dependable…hall wires are a common failure point.  Running without hall wires make a lazy ebike builder forced to pedal a little bit to get his rig going.

 DIY Ebike Batteries

ebike pack

Many DIY Ebikers want the best performance per dollar they can find. Since professionally-built ebike battery packs with Battery Management System (BMS) are expensive, DIY Ebikers often prefer to build it themselves without a BMS. This results in a rats-nest of wires they must access, so that they can do the occasional balance charging to keep this entire cluster puck from blowing up into flames. Believe it or not…the above pack was build from a very skilled builder…but to run Hobby King packs in this type of huge cluster requires a lot of wires….OMG! what a mess.

(read article on building your own 18650 battery pack)

Solutions for less wires?

Buy a commercially available ebike pack with a built-in BMS protection.

 DIY Ebike Chargers – What a mess

Many DIY ebikers want high performance, but…they also want it cheap. They buy batteries with no built-in BMS and then balance-charge the mess of wires with a balance charger. To do this they need an RC charger (which was originally designed to be used out in the field, and fed with big 12-volt car battery), so when they are at home?…they have to wire their corded charger to a second corded box, known as a power supply (converts 120 volts AC into 12V DC) which results in more messy wires.

Here is a typical DIY Ebike Charging system consisting of Hyperion charger and power supply…actually this one is fairly tidy compared to most that I have seen.

Hyperion duo

Solutions for less charging wires?

  • Do not run a battery pack without a BMS…let the BMS deal with the cell-balancing and the balance wires.
  • Consider the Cycle Satiator , a powerful charger designed for ebikes.


Chinese Ebike Controller wiring nonsense


When you buy a controller it typically looks like the above pic. A bunch of unsightly wires coming out to handle all kinds of silly stuff such as cruise control, etc. The connectors are complete garbage. To start with, if you buy a controller that has connectors like this?… consider changing at least the main two red/black lead wires to a quality connector. ( read our story on ebike connectors) Another hint is that: after you have done your installation, do yourself a favor and just clip off the wires you did not use. Seems ridiculous but offering a product with this many wires is uncalled for and demands drastic action.

Possible Solutions:

Buy a controller that is not just a Chinese generic…spend the money it costs for a modern controller with less wires and more thoughtful construction. Demand innovation.

Consider an Adaptto system, the ultimate ebike solution on the market right now, containing controller, super sophisticated BMS and display screen, all in one tight, super integrated, and  compact package.  The Adaptto uses quick connects, has a myriad of features that makes you think these guys really understand ebikes, and is half the size of a traditional controller, with 3X the power of a typical Chinese controller, and includes features such as variable regenerative braking,  traction control, motor health monitoring…etc etc.  Finally, it feels like modern technology is touching ebikes.


Wire Clutter  on  the Handlebars


The modern-day pedal bicycle should be simple and clean… usually just a brake cable or two, and perhaps a shifter cable to the handlebars, but…elegantly tucked-in and hidden as much as possible. Bike manufacturers for years have been trying to find ways to simplify and lessen the wire clutter to the handlebars.

Enter the DIY Electric Bike…swarming with cheap Chinese tech, and you get a multitude of wires coming to your handlebars. Yeah, it is a different look…but more than just the look, upkeeping and troubleshooting all those wires can be a royal pain.


Most throttles are on the handlebars, and I have not seen a good looking one yet from China. They are either twist grip or thumb lever and, require a set of 3 wires to run down to the controller.


Possible Solution?  Consider a pedal assist system where the throttle is controlled by how hard or how fast you pedal.

ON/OFF switches should be a required safety item on all ebikes but most DIY ebikes actually don’t have them, and the ebike is turned on by connecting a plug and socket together.

Very few Chinese controller suppliers have decided to sell controllers with on/off switches on the controller, so…if you’re NOT lucky enough to have a controller with an integrated on/off switch, you have to buy a separate overpriced on/off switch and run an additional  wire to the wiring harness coming out of your controller to your handle bars. These wires send a signal to the controller telling it to shut down.

on off switch4onoffswitch2 onoffcrise onoffswitch3speed



Whoever invented ebike safety etiquette has decided that an E-brake is critical safety equipment on an electric bike. Basically an E-brake means when you hit one of the brake levers, the motor power is momentarily cut off…this makes it hard to accidentally hit your brakes and the throttle at the same time. This requires (of course) two more sets of  wires going from your controller to your handlebars, to an inevitably cheap and low-quality brake handle…and just like on and off switches, I have yet to see a high quality E-brake handle out of China:


Ebike Lights

Popular in the ebike DIY crowd are lights that are proprietary to ebikes. Like front and rear lights with wires that lead directly to the ebikes battery pack. The idea is that you can use a nifty voltage converter built into the lights, so you don’t need a separate light battery to charge. The problem is that they require still more wires going from your handlebars to your battery.

Possible Solutions – If you’re using a Cycle Analyst, wire your lights to the Cycle Analyst wire port to minimize wiring.

Save money and complexity and buy a battery powered light…who cares if you need a separate battery.


Cycle Analyst

cycle analyst

Here is a piece of Canadian Tech that many DIY ebikes incorporate to keep track of their battery usage on the bike. The Cycle Analyst can also display speed, and if you are doing this with a direct drive hub motor with hall sensors, it can do it wirelessly…Hallelujah!

But you still have to run a set of wires to the Cycle Analyst, either with the direct plug-in version, or stand alone version. Also the Cycle Analyst has another clump of wires coming out the back of it…which adds to the wire clutter on the dash.

Possible Solutions to reduce wiring of the CA –

  • Use all the functionality of the cycle analyst to reduce wiring clutter.
  • seek a more integrated or wirelss solution



I wonder…if I ripped apart one of my DIY ebikes, and took all the wires out and connected them together and stretched them down the block…would it stretch a mile?

Very rarely do I harp on the draw backs to building your own electric bike. If you are focused on good performance at a cheap price…DIY is definitely the way to go.

But…be prepared to deal with the wiring headache…which I see as by far the biggest drawback to building an electric bike.

In the next few weeks I will be writing a series of stories about ebike wiring in the DIY scene, and what a mess it has become. Wires are like pollution, and we need to eliminate as many of them as we can.  We are supposed to be in the wireless age.


Written by Eric Hicks  / Editor, April 2015



Eric has been involved in the electric bike industry since 2002 when he started a 6000 square foot brick and mortar Electric Bike store in downtown San Francisco. He is a true believer that small electric vehicles can change the way we operate and the way we think.


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