First 100 miles on my E-Bike: what I learned

December 30, 2017June 5, 2018 Yilun Zhang64 Comments

In the last 6 months, my wife and I traveled to Europe and Asia on 2 separate occasions. I saw people riding bikes everywhere. That by itself is not surprising. What did surprise me however, was that almost every single bike I saw had an electric motor and battery pack on it. I had never seen anything like that state side. I have seen electric scooters riding around in Toronto, but those were incredibly bulky and wasn’t very pleasant to ride. On these new bikes, the battery packs and motor had such a compact package that it almost feels like it’s intended as part of the bike.

Unfortunately, I didn’t get a chance to ride on one of those electric bikes during my time in Europe and China, but they left an impression on me. I started doing some googling. It turns out there are more than 200 million E-Bikes in the world. That’s way more than I expected. Annually, the world sells 34 million E-Bikes. Asia dominates the market, accounting for close to 90% of worldwide sales. Europe comes in at a distant second, accounting for 5%. North America has <1%, accounting for a measly 152,000 units in 2016 [1]. I was curious why these E-Bikes have such a high level of adoption elsewhere, but almost non-existent here in North America (in both US and Canada).

To truly understand, I wanted to experience riding an E-Bike first hand. I decided to acquire one and use it as my primary form of transportation for a month. To make sure I have good metrics to reference, I used Strava to log all my rides.

So far, I have ridden about 100 miles with a good mix of bike trail and roadway. I would say that overall, it’s been a very positive experience. Here is what I learned during this process.

Build vs Buy

I originally thought I could just buy an E-Bike online, but the prices were significantly higher than I initially thought. I was budgeting around $500 to $1000, but buying a turn-key bike off the shelf often cost more than $3000, and can go up to $5000. There are cheaper ones, but they are all cheap for a reason. I didn’t want this experiment to be ruined because I cheaped out and bought something subpar. Moreover, I wanted a mid-drive solution for performance reasons. This way, I can take advantage of my bike’s existing gearing. To better understand the differences and trade-offs of each setup, click here. I found a few reputable vendors selling E-Bike conversion kits. They often have higher spec motors for a much cheaper price. After some research, I decided to build one myself instead. I bought the bike from a local guy on craigslist, and the conversion kit (including battery + charger) from LunaCycle. Having now gone through the experience, I would definitely recommend the build route. It was such a cool learning experience and you just get much more value for your money.

Below are all the parts I bought:

Part	Link	Price ($)
Bicycle (Used)	http://www.sears.com/iron-horse-29inch-men-s-bike/p-00665027000P	$200
BBSHD 1000W Drive kit	https://lunacycle.com/bafang-bbshd-1000w-mid-drive-kit/	$679
Battery	https://lunacycle.com/52v-panasonic-11-5ah-or-13-5ah-shark-pack/	$496
Charger	https://lunacycle.com/52v-3amp-luna-mini-charger/	$55
Total		$1430

Here are some photos of my converted E-Bike once complete. I really like how it turned out:

The build itself wasn’t super difficult, but did take significantly longer than it should have (about 10 hours over the course of a week). This is mostly due to my own inexperience working on bicycle. Most of the time wasted trying to find the right tools and parts. Realistically, the build can be done under 2 hours. Here are some tips to save you some trouble:

I didn’t realize I needed special tools to work on a bike. I had to buy this set from Amazon (link)
The spanner I had didn’t have enough leverage and grip to take off the bottom bracket. I ended up finding this Sheldon Brown method on youtube that worked wonders (link)
The battery case didn’t fit onto the water bottle mount so had to buy another bracket to offset its position. (link)
When taking off the chain, and afterwards realizing I shouldn’t take the entire pin out. Spent an hour trying to get pin back in until I gave up. Ended up buying a quick link from KMC (link).

Overall riding experience

Since finishing the build, I have put about 100 miles on the bike over the next 2 weeks. The riding experience have been very positive. I am really surprised at how much better the riding experience is, Below are some telemetry data from a typical ride that I do from home to work:

I think the best thing about my E-Bike is that it increases my baseline speed when riding. I’m still exerting effort pedaling, but now I stay in the 20-30 MPH instead of 10-20 MPH range. With the help for an electric motor, getting up to speed takes significantly less effort. I can also power through hills without significant loss in speed. As a result, I find that I am enjoying the cycling experience a lot more.
My second favorite thing about the E-Bike is that it’s really nice to be able keep up with traffic on the road, particularly when there isn’t a bike path. It feels much less scary.
My third favorite thing is that I can get to work in basically the same amount of time as driving. On my E-Bike, it takes 22 minutes to get to work (7.5 miles). It takes me 15 minutes to drive there. It would normally take me close to 40 minutes on a regular bike. While the E-Bike lacks the top speed, I make it up in stop and go traffic when I can always skip to the front of the traffic light.
I’m also not sweaty when I get to work, no need to take shower.
My 13.5 Ah battery is good for about 50 miles, way more than most people commute in a day. However, I typically recharge after 30 miles. It’s not good to completely drain the lithium ion battery pack.
At 750W setting, the bike already feels plenty fast. I have reached speed of 35 MPH pedaling on my bike, that’s only on a medium power assist level. I honestly don’t think it’s safe to go much faster than that on a normal bicycle.
For flat city riding, I really only need 1 gear. On cities with more hills, I can see the need for 3, but 9 gears in the back is overkill.
My biggest surprise was that pedaling felt much better than using the throttle. Even though I can actually go faster when I use throttle, I still compelled to pedal. I think the bike ergonomics is just designed for pedaling so it felt more comfortable, or maybe my preconception is still that I am on a bicycle, so I should pedal. I did feel a little weird being on the bike path with other bikes and passing them without pedaling.
I tend to use throttle only when I want to accelerate quickly off a red light

Economics of owning an E-Bike relative to car:

Riding a bike makes is unsurprisingly much cheaper relative to driving a car. By my own estimates, riding an E-Bike cost ~$0.14 per mile (assume battery pack last 500 cycles and routine maintenance on brake pads and rotor) where as driving cost $0.86 per mile. When I replace my 15 mile commute from car to bike, I am able to save ~$2800 each year. The math here is a little fuzzy and have quite a few assumptions baked in, but know that the savings come from the following areas (I might write a more detailed post on this later):
- Most of the savings come from lower depreciation and maintenance.
- No insurance or parking required.
- Electricity is much less costly than gasoline.
It would still be difficult to completely replace car here in Arizona
- Summer is way too hot to ride a bike. Riding in 100+ degree sun is just not my idea of good time.
- Phoenix is fairly spread out. Going anywhere outside of work and local restaurant would be better suited in a car. I can see E-Bike being adopted much faster in a denser city like New York, Boston, San Francisco, or Toronto

Why adoption hasn’t happened yet

If the ride is so great and economics so favorable, why haven’t I seen more adoption here in US and Canada? If I have to guess, I think there are a few reasons why:

Current E-Bikes are still too expensive relative to other transport alternatives and there is a lack of available financing options to smooth out the capital outlay. On average, an E-Bike cost between $3,000 to $5,000. In China, your average E-Bike cost around $500. Most Americans just don’t have that type of money saved up in their bank account for what is currently a luxury item. In some ways, a car is actually more affordable than an E-Bike because you can finance a car with $0 down.
The current E-Bikes are too easily stolen. This is especially a problem in the major cities where E-Bike make the most sense. It just doesn’t make sense to use the same lock mechanism to secure a bike that is $200 vs $2000. I think there is more that can be done on that front for E-Bike. For example, why not lock up the powertrain so the bike can’t be pedaled when off, or notify me on my phone when my bike is on the move while locked.
Off the shelf E-Bikes performance are too low. Most of the commercial E-Bike uses 250W or 350W motors, because that’s what the European specs are. While that amount of power is able to achieve 20MPH range, it does take its time to get there. In the US, with the open roads, that’s simply not enough power to keep up with traffic. Quite frankly, they still feel like a plain bicycle and it’s a bit boring to ride. Higher adoption require more power.
E-Bike conversion kits feel more like a prototype than a complete product. The approach most E-Bike builders have taken is to retrofit an existing bike with a motor. While that is often times the most economical option, the bike does feel like a mishmash of parts when done. While they work, but they don’t work as well as you would like. For example, the transmission on an electric motor doesn’t nearly need as many gears, because there’s already an electric power to supplement power. The brakes are often too soft to handle continuous elevated speed. What ends up happening is that I spend more money overtime to upgrade the bike to my desired state. So far I spent about $1500, including parts and tools, this is accounting for a fairly cheap used bike on craigslist ($200). Had I bought a new bike, I would have had to spend probably close to $1900. To make it exactly the way I want it, I estimate that I have to spend an additional $800 to get install IGH, bigger brakes, and more efficient tires with less rolling resistance.
Software is a step behind the hardware. There are bunch of vendors that are selling kits that have more power, but the electronics are often incompatible. They just don’t feel like the complete package “that should just works”. Most of this is on the software side. Making software + hardware work seamlessly together is hard when everything is built in house. It’s much harder when parts are built by different manufacturers without any real standards in communication protocol. Example:
1. My battery charge % being displayed doesn’t reflect accurately because the battery pack is 52v instead of 48v to eek out additional power.
2. My display has options to monitor each cell’s charge to ensure that they are balanced. But because the battery pack is custom built by state-side vendor and doesn’t use Bafang’s BMS, those displays don’t work.
3. The watt meter also doesn’t get reflected properly.

In order for E-Bike to really take off, I think there is a need to design it from the ground up. Instead of building the motor and battery pack around the frame, the right way to design an E-Bike is to build the frame around the motor and the battery pack. Ideally, the battery pack should be integrated into the frame for a sleeker look. The transmission used should be an Internal Gear Hub for higher reliability, and brakes need to designed to operate in the 30 mph range. Headlight and taillight should be integrated into the bike for night riding.

More importantly, the bike as well as its accessories should also be thought of as an iphone instead of just a purely mechanical system.

I should be able to program different modes of operations directly on my app (sports mode, eco mode, etc.).
Over the air update should be possible as power electronics continue to be refined.
A companion app should accompany the bike to provide detail telemetry data and possible error diagnosis.
My battery charger should be smart enough to balance the battery charge at 80% instead of waiting until it got to 100% and help prolong the life of my battery pack. Battery Management Systems (BMS) on an E-Bike still have a lot of room to grow.

What’s next

I am however fairly optimistic that these things will be done in a relatively short time scale. A lot of these technologies are starting to show up in the automotive space. It’ll likely take some time for them to flow down to a price point where it make sense for an E-Bike application. At that point, I think E-Bike will become a much more integral part of people’s lives.

In the meantime, I plan to experiment with a few other things for this bike:

Tune/program the motor controller to vary the motor wattage and petal assist setting to understand tradeoff
Build my own battery pack with more capable BMS
Update the bike drivetrain (bigger brakes, make use of Internal Gear Hub, more suitable tires for city commute)

Reference:

[1] https://www.nextbigfuture.com/2017/04/electric-bikes-could-grow-from-200-million-today-to-2-billion-in-2050.html

How blockchain can help make healthcare data more useful

September 26, 2016August 16, 2017 Yilun ZhangLeave a comment

Patient health data is the single biggest bottleneck for advancing healthcare

Healthcare is going through a tremendous phase of innovation. Healthcare data is finally coming online due to the government mandate to adopt Electronic Medical Records (EMR). AI and machine learning is advancing at an exponential rate. Soon, precision medicine will finally become reality. Doctors will be able to better diagnose my condition based on data from millions of research papers that no single human can possibly read in his lifetime. They will prescribe me the best treatment available not because it’s “what generally works”, but because millions of other patients who are similar to me in age, sex, and genetic makeup saw a positive impact from the treatment.

While I have no doubt that is the future, I think one fundamental thing that is often not talked about is that these advancements all require a fundamental ingredient, holistic patient health data at scale. In my opinion, it’s not the lack of algorithms, but the lack of access to useful health data that is the single biggest bottleneck for advancing healthcare treatment. Any researcher will tell you that a simple algorithm with lots of data will generally hold more predictive power than an complicated algorithm with little data. As far as I know, this type of data just simply doesn’t exist today for research. This is because sharing healthcare data is very hard. There are a number of reasons for this:

Tesla-SolarCity merger: why Elon Musk is playing chess while everyone else is playing checkers

July 12, 2016November 22, 2016 Yilun Zhang3 Comments

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Tesla recently put out a $2.8B bid to acquire SolarCity. The initial reaction was less than favorable. Here are some of the headlines:

Is Tesla’s SolarCity Move Actually a Bailout? – Bloomberg

Why Tesla and SolarCity Have an Elon Musk Problem – Fortune

Tesla’s Deal With SolarCity Is A Remarkably Bad Idea – SeekingAlpha

At this point, a lot has been written about the short term impact of the deal. However, I haven’t really read anything that explored the long term potential of the product that the combined company can build together.

By putting solar panels together with battery storage, the 2 companies can create an end to end solution that allow people to produce, store and consume clean energy at a cheaper price than what they would have otherwise paid for.

I think in order to understand the value and feasibility of it, the most important thing is to figure out the unit economics of solar panels and batteries. Electricity isn’t sexy or entertaining. In order to achieve mass adoption, the solution needs to save people money and be viewed as an asset. To get a high level understanding, let’s start ask a few basic questions about solar panels and batteries.

Conviction vs. Stubbornness

February 21, 2016January 27, 2017 Yilun ZhangLeave a comment

It’s hard for outsiders to tell the difference between conviction and stubbornness.

Both have strong belief systems, but their mindset is vastly different.

I was going to write a long blog post about it, but realized I can distill it down to the following:

Someone with strong conviction is receptive to new information. He has strong opinions but is ready to be convinced otherwise.

Someone who’s stubborn is on his own island. He closes his mind to all other possibilities because he can’t possibly be wrong.

Conviction = opinionated
Stubbornness = bigoted

Don’t be a bigot.

How I structure my requirements – with real-world example

September 16, 2015September 16, 2015 Yilun ZhangLeave a comment

On writing requirements

How do you write good requirements? What’s your process for writing them? These are often the first question people new to PM ask. And rightly so! A PM’s primary job is to figure out what to build and then write a set of clear instructions for the engineering team to actually build it.

The ability to write complete and clear requirement cannot be overstated. It gives you more credibility with the engineers, reduces preventable rework due to missed requirement, and most importantly, frees up your time to focus on future product releases.

There are lots of instructions on how to write a typical user stories in the Agile environment. However, I found that they either stay super high level, or give examples that are overly simplistic and doesn’t take into account the complexities of real world development.

I am a product manager…I don’t do any real work.

May 14, 2015August 23, 2015 Yilun Zhang1 Comment

“I am a product manager. I do a bunch of things…just not any real work.” I’ve tried that line a few times at cocktail parties when the question “so…what do you do?” invariably comes up. On the good days, that usually gets a faint laugh from everyone. The statement is meant to be facetious, but there is an element of truth to it. In fact, that’s exactly what my mother thinks to this day. In her mind, unless my job title has the word engineer, lawyer, doctor, or sales in it, it’s not a real job. She keeps a spare bedroom in her house. I’m convinced it’s because she believes it’s only a matter of time before my company figures out I’m actually useless and show me the door.

While I don’t think I will be out of a job soon, there is a certain amount of truth to that. The way product managers add value is very nebulous. In my daily work, I tell people what to build, but I don’t actually build anything. I do a lot of selling to stakeholders, but I don’t actually sell any products or bring in any money for the company. I tell people how to do a bunch of things, except they are 10x better than me at doing it. So why should a product manager exist at at?

In my view, a product manager is the equivalent of an amplifier in a sound system. By itself, it’s completely useless, but given the right components around it, the amplifier is the difference between a home theatre system and a sound system that is able to fill a 2,000 people concert hall. If I have to distill down the role of product manager into a tweet, it would be to:

10x the productivity of the people I works with

The philosophy has significant implication in the way I approach work on a daily basis. Below are 3 rules that I follow to ensure that I get the results I desire.

Hacking the job search process

February 18, 2014August 23, 2015 Yilun Zhang2 Comments

A new beginning

I recently accepted a job offer to join a healthcare technology start-up called Medivo. This concluded my 4 months job search. It was actually the first time I had to find a job after since graduating from college. Before this, I ran my own tech start-up called Fleetbit. Compared to my experience applying for internships as a student, I found that I had to work much harder to get that initial interview. In hindsight, this made sense. In college, the pool of competition is much smaller and the firms have a mandate to hire young talent every year through campus recruitment. Those rules don’t apply anymore once I am out of school.

Looking for jobs is hard!

During the first month of my job search, I had very limited success. I mostly applied online. Out of the 10 jobs I applied to, only 1 of them got back to me for an interview. Despite several iterations of improvement on my resume and cover letter, the conversion rate did not improve at all. After a month, I concluded that my resume was not the issue. Instead, I needed a different way to get the employer’s attention and establish credibility. Going through the regular recruitment channel was not a good option.

Having started Fleetbit, I knew I had a unique and compelling story to tell. My hypothesis was that if I can make my case directly to the decision maker instead of going through the recruiter, my success rate will dramatically improve.

What I learned in the past 2 years about being an entrepreneur

October 22, 2013August 23, 2015 Yilun ZhangLeave a comment

Recently, I exited from Fleetbit, the company I co-founded right out of college. While the company didn’t turn out to be the kind of wild success we initially hoped for, I am still extremely proud of what my co-founders and I have accomplished over the past 2 years. The company is profitable and has a stable revenue stream from more than a dozen customers; our product is live and stable; and I think we helped push the taxi industry forward. Had Fleetbit not been around, I don’t think any of the existing dispatch software vendors would have embraced mobile as quickly as they did.

The past 2 years has been an amazing journey that was filled with both joy and disappointments. The company was featured on national press like Techcrunch, National Post, BNN, etc. I got a chance to go to China and pitch Fleetbit to prominent VCs and executives. Last but not least, the team drove all the way from Toronto to San Francisco then back, chatting with local taxi fleets in each city along the way.

Despite the modest success we achieved with Fleetbit, there are also deep scars on my back from this experience. They are my badges of honor, but those scars also serve as stern warnings for me and any other aspiring entrepreneurs looking to start a tech company. Below are the 3 key lessons I learned during the past 2 years.

Where is MOOC heading next?

September 9, 2013August 23, 2015 Yilun Zhang1 Comment

Massive Open Online Courses (MOOCs) like the ones offered on Courera, edX, and Udacity are all the rage these days, and rightly so. In my opinion, MOOC is the most important innovation since the dawn of the internet age. For the first time ever, we can distribute quality Ivy League education content to everyone with a desire to learn..for free. What’s more amazing is that unlike other industries where incumbents are generally fighting against disruptive changes, the elite education institutions (i.e. Harvard, MIT, Stanford etc.) are actually leading the movement.

However, don’t mistaken MOOC as a platform that simply allows millions of people to watch lecture videos online. This is merely the first step, the first hour of the first day in God’s work. To get a glimpse of how technology can fundamentally change the way we learn, watch Conrad Wolfram’s TED talk here.

However, before MOOC gets there, there are still massive problems to solve. Currently, their immediate focus is on refining their core infrastructure. For example, how do we streamline the course production process to help reduce its launch time? How can grading be done effectively for assignments that doesn’t have a clear answer? How do we reach people in China when Youtube is blocked by the government? These are the problems that aren’t sexy to solve, but are mission critical elements that will make or break the user experience.

THE BYSTANDER

Casual observer of the world around us