Its been about a year since I built my Bafang conversion e-bike and I still enjoy riding the bike. I am impressed with how powerful the 750 watt motor is and the range the 840wh battery provides. However, the Bafang conversion is missing one key feature that I’ve become very used to on my Bosch e-bike. That is a continuous range estimate on the control display. Without a range estimate provided by the e-bike system, you have to guess the range left in the battery based on your experience.
So it finally happened. I ran out of juice while riding the Bafang. I must admit it came as a surprise. I started the ride with 3 out of 5 bars displayed on the battery indicator. Three out of 5 bars means I should have somewhere between 40-60% of the battery’s charge left. However, after about a mile into my ride the battery dropped to 2 out of 5 bars meaning I had a 40% charge. Still, I wasn’t worried sine I was planning an out and back ride. I simply planned to turn around when, or before, I reached 1 bar. My plan was to use 1 bar going out and 1 bar to return. However things didn’t go as planned.
To my surprise, about 10 miles (16 km) out while climbing a hill the battery dropped to 1 bar. Only 10 miles (16km) on 1 bar? That was unusual. Still I wasn’t worried. I just turned around and headed home. If I used 1 bar going out the remaining bar should get me home. Right? Wrong! Only a few miles more while climbing a short steep hill the battery indicator started flashing empty. No way! I should get more than 15 miles (24 km) on a battery that was at least 40% charged when I started. Was the Battery Management System saving power to protect the battery from completely discharging? There was no way to tell. Not willing to take a chance on damaging my battery, I shut off the power and started pedaling my dead e-bike home unassisted. Luckily it wasn’t as hard as I expected. The motor didn’t add much drag and the additional weight was only noticeable on climbs. About half way home I turned on the system again. What was happening? The display showed 1 bar again and I was able to make it home on assistance level 1. In my opinion, not having a continuous range estimate is a BIG DESIGN DEFICIENCY in the Bafang system, especially when for some unknown reason the first half of a charged battery provides a lot more miles than the last half of the charge.
It is a bit of a paradigm shift when it comes to thinking about e-bike frames. It’s true that high quality carbon fiber bicycle frames are known for being light weight with lateral stiffness and vertically compliance. But, you have to ask yourself if that is important when it comes to an electric bicycle. In my case I wanted all those feature on my non-electric bike, but when it came to purchasing an electric I didn’t need or want to pay for these features.
Light Weight: The difference in bicycle frame weight is highly overrated. Since the difference in weight only accounts for about one or two watts of additional power, the reason bike riders lust for the lightest carbon fiber bicycle possible is to lighten the load when climbing hills. Similarly, the number one reason most people give for buying an electric bike is to make hills easier. Although you may need the lightest possible bicycle you can afford or an electric bike to make it up hills easier, you don’t need both. The lightest e-bike with a carbon fiber frame isn’t necessary when it comes to hills because the weight savings just isn’t significant when a rider is being assisted by an electric motor.
Lateral Stiffness: In theory a stiffer frame is more efficient as less energy is lost to the frame flexing. This is most important when pounding the pedals because it can create energy robbing flex. However, since the rider is being assisted by an electric motor there isn’t a need to pound the pedals. As a result, there isn’t a significant energy loss by the rider due to frame flex.
Vertical Compliance: When I think of compliance, I think of comfort. But handling is also a part of compliance. I find that tire size and pressure make a more significant contribution to compliance than frame materials. A wider tire with more air volume and lower tire pressure gives me a sure footed and comfortable ride. Therefore, a frame with tire clearance that will accommodate wider tires is much more important than having a carbon fiber frame.
Durable: All other bicycle frame materials such as steel, aluminum, and titanium are more durable than carbon fiber. A significant scratch in a carbon fiber frame can ruin the frame, whereas a scratch in the other frame materials just adds character and to the story of the frame.
Precision Engineering: Steel, aluminum and titanium are easier to precision engineer than laying up carbon fiber.
Recyclable: Carbon fiber is not recyclable while the other bicycle frame materials can and should be recycled.
Reduced cost: Carbon fiber frames are expensive to make and, as illustrated above, offer no significant advantage over other frame materials when it comes to e-bikes. The savings could be used for better components or just more money in your pocket.
The bottom line? Ask yourself if there are any real advantages to a carbon fiber e-bike. After careful consideration, I think you will agree that a carbon fiber e-bike is not worth the additional expense over other frame materials.
As I mentioned in my post Thumbs Up to Bafang!, one of the outstanding features of the Banfang BBS02 conversion kit is that it’s configurable by the user. Many changes like configuring the bike as a class 1, 2, or 3 and other basic features of the bike can easily be configured from the display. However, with a laptop computer, a special USB programing cable and the Bafang Configuration Tool Software the Bafang motor controller can also be reprogramed by the user to improve the usability and performance of the e-bike.
My goal here is to only make you aware of the possibility of reprogramming capabilities of the Bafang controller. Detailed instructions can be found from other sources below:
However, be warned that reprogramming your Bafang system is not without risk. You can destroy the controller if done incorrectly. So, read the guides and do not attempt to customize your settings if you don’t fully understand what you are doing. Proceed at your own risk.
Have you ever wondered how accurate e-bike range estimates are? To find out, I put my Bosch equipped Cannondale Synapse Neo 1 to the test. Assuming the initial estimate is based on nearly ideal conditions with a relatively flat terrain, I chose an out and back route along the Torrey C. Brown Rail Trail, MD and Heritage Rail Trail, PA with a 1,237 foot elevation gain for my test.
With a fully charged battery and the assistance level set at Eco (lowest assist level) the Bosch system estimated that it could provide assistance for 126 miles (see photo on lower left). While I wanted to believe Bosch’s estimate, my route was only 80 miles, giving me a good margin for error. Hopefully, if Bosch’s estimate turned out to be overly optimistic, the shorter route would save me from pedaling a dead e-bike back to my starting point.
The Results? I was pleasantly surprised. After nearly 80 miles (78.60 miles to be exact), I had 3 out of 5 bars (40-60%) left on the battery and an estimated 49 miles remaining (see photo lower right) slightly exceeding the initial estimate.
In the final analysis, the initial estimate was very accurate. In fact, I have to wonder, with about 50% of the battery left, why I didn’t have another 80 miles of assistance remaining. My guess is that Bosch has built in a safety margin to keep the rider from running the battery until it’s completely dead.
While e-bikes might not be right for everyone, they are a super fun and easy way to get around. They also can help you do more and go farther than you ever thought possible on a bicycle. Here are a few reasons why I ride an e-bike.
Safety: I admit it, on my traditional bike I sometimes ride on less desirable roads with more traffic simply because they offer the shortest and flattest route to get to my destination. However, that all changes when I ride my e-bike. Now, with my e-bike I find I’m choosing routes that I really enjoy and feel safe riding because I’m no longer concerned about avoiding steep hills or adding additional miles to my route.
More Willing to Challenge Myself: With an e-bike I find that I’m more willing to challenge myself as a cyclist. In the past, I rarely pushed myself to my limits. Instead, I would always “play it safe” and leave a safety margin to ensure I had enough energy or strength to make it back home. With my e-bike I can push as hard as I like and I only need to ensure that my e-bike battery has enough juice to get me home if I fatigue.
More Range with Less Effort: With an e-bike I can ride at the same speeds and distances with less effort than a traditional bike. For example, in 2015, I cycled coast to coast across America on a traditional bike. Click here to read that story. Unfortunately, about a week later I was struck from behind by a car. Click here to read that story. Now in my seventies, while I am not sure if I could do that ride again on my traditional bicycle, I am very confident that I could still do it on my e-bike.
Energy Efficient Transportation Alternative: Many times I will opt to use my car over cycling because I don’t want to show up at my destination all sweaty. Since I can cycle with less effort on my e-bike I can avoid undue perspiration, so running errands on a bicycle is less problematic.
Speed: I generally don’t ride my e-bike much faster than I ride my traditional bike simply because I find that drivers are prone to misjudge my speed if I ride faster. However, when necessary, I know I can cover the same distance more quickly while the effort remains the same on an e-bike. This is particularly useful when bad weather is approaching or when losing daylight.
Wider Access to Cycling: I was recently talking to a women who had stopped cycling because she had a steep hill at the start right out of her driveway. She no longer has the capacity for the strenuous effort of that climb. E-bikes are particularly useful for older riders to continue riding while limiting/controlling the physical demands.
I am an average recreational cyclist and I usually only average about 100-125 watts of power on my traditional bike. Before you laugh, remember that I am a septuagenarian. And of course, that’s my average so there are times when I pound the pedals and produce more power.
The thing to keep in mind on an e-bike is that it is “pedal assist”. So the total power output is the combined power of the rider and the motor. In my case, my Class 1 – 350 watt e-bike and my 100-125 watts produce more than enough power to meet my day to day cycling need. In fact, it feels like I’m riding on a tandem with a pro cyclist.
Think about it, a well trained pro cyclist can produce about 400 watts of mechanical power for sustained periods and up to 1000 watts for short efforts like a sprint to the finish line (see Harnessing The Power Of The Peloton In The Tour De France -forbes.com). So, it only stands to reason for normal day to day riding on an e-bike you would not need more power than a pro cyclist.
So why are some e-bike vendors pushing large motors? Honestly, I don’t know. My guess is to help their product stand out among the competition with an uninformed buyer like I was when I purchased my first e-bike. Don’t be seduced by an overpowered e-bike. They are more expensive, heavier and consume more energy.
The first change I made to my e-bike was to yank the tubes out and convert it to tubeless. While I made the change primarily to reduce flat tires, I also benefited with reduced wheel weight and lower rolling resistance, which both contribute to saving watts and increasing range.
I am always amazed at how I can increase my power output and feel like I’m not working as hard simply by increasing my cadence. Yet to my surprise, the same holds true with pedal assist electric bikes. My Bosch motor has a sweet spot around an 85 rpm cadence that will provided the longest range if everything else remains the same. So pedal faster, not harder, and go farther!
I was shocked how my e-bike range was reduced during the colder winter months. While I don’t have much control over the outside temperature, I’ve found that keeping the battery warm can increase the range up to 20% or more. Adding a neoprene cover over the battery provides thermal protection that will keep the battery warm and maintain optimal performance during cold temperatures. Conversely, high temperatures also have a negative impact on e-bike batteries. When you do have to ride in hot or cold conditions, storing an e-bike battery at room temperature before starting the ride will also increase the range.
Perhaps the quickest way to kill an e-bike battery is to completely discharge the battery then put the bike in storage. If the battery is completely discharged and left for an extended period of time it may become unrecoverable and may not take a charge. While a good battery management system should not allow the battery to become fully discharged, lithium-ion batteries self-discharge and lose their charge over time which could make the battery unrecoverable.
Don’t Leave the Battery on the Charger
On the other hand, don’t leave a battery on charge after it has reached a full charge. While most smart chargers will stop charging once a battery is fully charged, overcharging a lithium-ion battery can have disastrous results, like busting into flames. Once the battery is charged disconnect the charger. I set a timer to remind me to disconnect the charger when charging is complete so I don’t forget.
Don’t Store the Battery with a Full Charge
Similarly, don’t store a fully charged battery for long periods of time. Since I generally don’t ride my e-bike much in the winter. I discharge my battery to about 30-60% in the winter. It helps to improve battery life. If I do go for a ride, a 30-60% charge will generally give me enough juice to get me where I want to go and back.
Store the Battery in a Dry Place at Room Temperature
Finally, store the battery in a dry dry place away from direct sunlight at room temperature. The battery should also be recharged at room temperature. When transporting an e-bike it is important to remove the battery from the bike and store it safely in the vehicle. On a recent bike tour along the Florida Keys, I left the battery on the bike on the carrier on the back of my vehicle in the hot sun and through a rain storm. I was lucky that my battery made the trip without harm.
I want to tour with my e-bike so the range the battery will provide is a very important factor for me. Unfortunately, e-bike batteries can be the most confusing component of the bike. For example, my battery is a 48 Volt, 840Watt Hour, 17.5 Amp Hour battery. But what does that mean? While Bafang USA Direct states that it provides, “Up to 840-watt hours for an incredibly long range,” that really isn’t much help.
E-bike manufacturers tend to focus on watt hours. However, range cannot be determined by simply dividing a battery’s watt hours by the watts of the motor. Range will vary widely based on many factors including type of bicycle, rider posture, total weight, tires, riding speed, pedal assist level, terrain, riding surface, prevailing winds, etc. So while my battery might provide power for an hour running full blast on throttle, it may also provide assistance for 100 miles or more on assist level 1. Only experience will tell the true range of my bike and battery.
However, I have found a very useful tool for estimating the range of a motor and battery combination. While the site is Bosch specific, it can provide an idea of what range a motor and battery can provide under various conditions. Check it out at https://www.bosch-ebike.com/us/service/range-assistant/ or click here.
When I converted my Cannondale road bike into an e-bike I didn’t fully appreciate the value of a light e-bike. While I understand why you would want a lighter traditional bike, I didn’t think that it applied to electric bikes. Right? The motor and battery do all the work so weight really doesn’t matter, does it?
Not really. It’s a catch 22. With an electric motor, as power increases e.g. 750 watt motor, there is a corresponding increase in the weight and power needs of the motor. Further compounding the problem, as the power needs increase the size and weight of the battery increases which also increases the power needs.
So it is more of a balancing act to find the optimal power for your needs. In my case, I find that my Class 1 e-bike with Bosch Active Line 350 watt electric bike with its 500 watt hour battery gives me all the power I need and more range than my Class 3 Bafang 750 watt motor with a 840 watt hour battery. Perhaps the biggest factor contributing to better range with a smaller motor and battery is my speed. Since speed becomes the biggest factor in range and the class 1 bicycle stops assistance at 20mph a lot of power is saved. See “What E-bike Class is Right For You? Part 3: Range” for a more detailed explanation of the relationship between speed and range.
So when it comes to e-bikes bigger is not necessarily better! Another consideration with heavier e-bikes is your bike carrier/racks. Many bike carriers/racks are not designed to handle the additional weight of your e-bike. Remember, you have a lot on money riding on that bike carrier.