E-Bike Industrial Design project (with survey)

Discussion in 'Electric Bicycles' started by Sheik Yerbouti, Jun 24, 2010.

  1. Hey guys,

    It's been awhile since I posted, probably about 2 years. Before I made 2 Happy time bikes with my buddy. Fast forward a few years, and now my class is working with Fuji bikes, to design the next generation of E-Bikes.

    We were broken off into groups based on the customer. A few friends and myself are designing our bike for the "Regular Guy" crowd. Not necessarily the gear head or the engineer. Just a guy who wants to use his car less and use an e-bike for recreational riding, short commutes, or running light errands. But we are trying to design with cost effectiveness in mind.

    Right now we are in the research phase of this project. And that's why I'm hear. You guys are the best source for information we need to get our projects off the ground. As I mentioned earlier, we are striving to find the balance between cost and a reliable, consumer friendly product. Think...the Honda Cub of e-bikes.

    Here's a real basic survey to gather some more general information if you guys wouldn't mind filling it out.


    So, the first question. Batteries. I know the bikes that are at our price point are mostly SLA (the Currie bikes). From what I gather, they're heavy, don't last many cycles, and don't last very long per charge. Lithium ion batteries are much more expensive from what I understand, but I don't know much about NiCad and NiMh. Somebody said the NiCad's are idiot proof in a different thread. How much is the upgrade from SLA to a different, more reliable battery?

    We are also investigating different ways to make e-bikes convenient and easier for commutes and groceries. Maybe a grease-less drivetrain. Belt or shaft driven?

    What would you guys like to see done in a lower priced bike, that is currently being ignored by products on the market now? Any other suggestions?

    Thanks again guys, you're a ton of help.

  2. safe

    safe Active Member

    My specialty is a vision I've been working on for four years now. The idea is to race electric bicycles on Go Kart tracks to make it sort of a BMX like sport. The power is to be limited to the perfect "sweet spot" between not enough power and so much power that pedaling becomes useless. These bikes would be designed to pass the Federal Ebike Law for street legal usage as well as run on the racetrack. (1000 watts input and 750 watts output)


    As for batteries, SLA is okay but it's heavy and the harder you use them the faster they wear out. NiCads are good, but they are still pretty heavy. Lithium is the best, but it requires more cost to get into and also more battery management to keep from having it fail prematurely. It's more or less a cost / performance analysis to decide what you want and what you can afford. I would not rule out SLA's for an ebike, but only if you plan on about 250 watts of motor power. Beyond that and you ought to jump to other chemistries.


    It would be great if you took an interest in Electric Bicycle Road Racing (EBRR) because I think the Chinese have pretty much already mastered the basic entry level ebike. To really create a unique "All American" product you might consider "thinking outside the box" a little.

    I'm here to help if you want to consider the idea more.

    I'd love to see my vision turned into an actual product. (even if by someone else)
    Last edited: Jun 24, 2010
  3. Hey safe

    While doing research I stumbled across your battery pack, with NiCad batteries. And you mentioned how you can disassemble your pack and replace cells as needed, instead of wasting a whole pack.

    This is a really great idea, I feel, for this project. I was hoping to get some particulars on the battery. I saw it was made out of PVC, so you pretty much put the batteries end to end and wire them all together? How exactly is one of those made? I could look into a way to design a battery pack that is really easy for the user to crack open and replace cells as needed. How do you check to see if a cell is bad, with a battery tester or multimeter?

  4. safe

    safe Active Member

    Yes. A multimeter will show that a bad cell has close to zero voltage. It's an "All or Nothing" thing too where the cells seem to either be perfect or go bad... not much in between.

    For a manufactured product it would lower your labor costs if you could simply make the tubes and then just stick cells into them. Most of the effort is in creating the PVC tubes and I have little copper pennies from before 1982 (pure copper back then) as contact points. The copper pennies are soldered directly to the battery wires, so there is very low resistance. Springs hold the cells pressed together much like in a flashlight. Harsh bumps on the road simply allow the cells to move around without breaking anything. What's nice about the solderless tube idea is that you have complete control over the pack right down to the individual cells. Most packs are soldered together and that means if one fails the whole pack fails with it. A bad bump and a soldered joint can come loose. Even with SLA's they are built up with multiple 2.5 volt subcells to make 12 volts. I've found that it's usually just one cell within the SLA 12 volt unit that actually fails first, so you end up wasting the rest.

    However, the "accepted" approach is to use battery management systems that monitor cells and do load balancing. So don't get the idea that what I've done is normal.


    I'd really like to get my Electric Bicycle Road Racer idea reviewed a little. I know it's a stretch in that people might be unclear about what such a bike is used for, but if you remember the history of BMX the bikes were sort of junior sized clones of Motocross machines. Over time a unique sport developed, but in the beginning people weren't too sure what the future would look like. I'd really love to get a "real" manufacturer to take a look at the idea. I'm not after anything in the way of money or anything like that and have no patents to worry about, this is just my hobby.

    You might be surprised at how popular the idea could be. The "Road Racer" look allows for custom paint jobs and that would spawn a whole artistic side to the bikes as they customize the look. Kids like bright colors.

    I can talk for hours and hours about it...
  5. Don't worry, my friend steve and myself are planning on looking hard at boardtrack racer inspired designs. We'll probably iterate it alongside other concepts.
  6. safe

    safe Active Member

    Yeah, what's with this whole "retro" look with the board track racer? I've noticed that the gas powered bikes do that and I've even seen some ebikes do it. I just don't get it... I suppose the idea is to get people to think that this new class of vehicles is now "being born" just like the board track racers were years ago.

    The Road Racer look is aerodynamic... a very different look.


    Kids are not going to like the "retro" look very much and I would suspect that they would prefer the brightly colored modern look. I suspect the "retro" look is most appealing to the older crowd. (which seems to dominate ebikes right now... Baby Boomers.... 50+ year olds)

    What age group are you targeting?

    You do realize that the majority of feedback you get from this forum is from older folks?
    (like myself... I'm almost 50)

    As I see it no one is attempting to sell to younger people and it's because ebikes are considered undesireable at this point to the younger crowd. There is nothing exciting about a WalMart ebike that can barely go 20 mph. In order to change the demographic profile of ebikes what is needed is something that appeals to them (like a sleek Road Racer design) and then a sense that there is some "quest" for competition involved with it. A young person likes to dream of winning on their machine. Usually by their 20's the young person starts to think about the rest of their life and you kind of lose touch with them (as a market) until they get old enough to be in semi-retirement.

    The primary introductory market for ebikes would be the 14-18 year old range. That's the point that you want to have an entry point. After that and you probably lose them.
    Last edited: Jun 25, 2010
  7. moondog

    moondog Member

    Here is some old dude feedback.

    The ezip setup and the Heinzmann hub both will freewheel allowing the bike to be easy to pedal without using the motor.

    So... a bike that weighs not much more than a regular bike that when riding you can not tell it is electric until you hit the switch.

    Then ride it like a regular bike knowing all the time youi can hit the switch if you want or need to and go 40 miles more.
  8. moondog

    moondog Member

    safe, what are you saying, the Trailz will barely go 20 ?

    My Trailz feels real steady over 20 mph. At 30mph I can let go of the handlebars and that bike is straight steady.

    The motor gets you up to about 16 or so then after that your on your own baby !

    I did slime tube and mr tuffy the wheels.

    The kids love those scooters. They don't need a gearbox because of the small wheel size.
  9. Joey

    Joey New Member


    "Fuji bicycles are now built in Taichung, Taiwan; Dong Guan, Guangdong Province in the People's Republic of China; and in Kutno, Poland by Ideal Bike Corporation."

    Ideal Bike Corporation Pingzhao Zhan -Chairman of the Board

    Will this e-bike be built, or assembled, in the USA by American workers?
    "Regular Guy" in America wants to know.:detective:
    Last edited: Jun 25, 2010
  10. Stan4d

    Stan4d Banned

    Could you source your demographic study that supports your comment?
  11. AussieSteve

    AussieSteve Active Member

    Sheik, a couple of questions.
    Rather than a setup with a drivetrain, have you considered using a hub motor? (Just noticed that moondog mentioned this too.)
    What output power are you planning?
    Finally, what sort of range are you looking at?
  12. We're going to base a lot of these answers off the user research we gather. I mostly wanted to pick your brains about the technical stuff. I'll be able to give you guys more specifics when the research aspect of this project is over. In the meantime I just wanted to generate some discussion and "get the ball rolling" you know. I appreciate all the responses.
  13. This bike is aimed at the walmart and best buy crowd. How many "regular guys" do you know that shop at these places? I'm sure most of them do, and very little in those stores is manufactured in this country. ****, half the time the food we buy isn't even grown in this country. I understand and appreciate your argument, but most of the people in the demographic I'm targeting with this project already buys a lot of chinese made items. There are other groups in my studio that are trying to target a different price bracket, and a different audience.

    Thanks for your response.
  14. safe

    safe Active Member

    I know I sound like I'm repeating myself, but from the beginning I've targeted the concept of the Electric Bicycle Road Racer as a WalMart product. If you go to WalMart and check out their existing electric pocket bikes you would see that they already try to sell into a teenage marketplace.

    The idea is to simply make a "faux road racer" electric bicycle that just so happens to actually work well. Sort of sneak the product in.

    It's not like we're selling Tobacco here... kids are going to ride around on the streets and do silly things no matter what products are available, but the idea would be to build something that was designed with actual understanding of what a good "road racer" might function like.

    Anyway... sounds like you have your mind set on the board track racer idea... I really don't think that a 16 year old will understand the appeal of "retro" styling. Older ebikers (40-60 year olds) like the idea of "retro" because it helps comfort them in their old age identification process. They think "ah, the old look was so cool... sort of like how my gray hairs are cool."

    I might be wrong but if I were to make an association I'd say:

    Board Track Racer Demographics - 40 to 60 year olds

    Road Racer Demographics - 14 to 30 years olds

    ...the people from 30 to 40 are so busy with their main lives that they usually don't have too much time for hobbies.

    WalMart bikes should appeal to children.
  15. safe

    safe Active Member

    Specific Battery Advice

    Here's a thought...

    Design the bike around two 12V 18Ah SLA batteries so that you can sell the bike cheaply at WalMart.



    The owner can then replace the SLA's (13 lbs each) with these Lithium cells (6.6 lbs each and double the Wh capacity after you consider the Peukert Effect). They are an exact plug in replacement product. That way you can sell the bike with a specific battery mounting that would work for either chemistry.

    And zero labor cost... :cool2:

    Design the motor so that it works optimally at 24 volts. (most people don't realize that with proper electric motor design 24 volts can do quite well)
    Last edited: Jun 26, 2010
  16. Stan4d

    Stan4d Banned

    Question for Safe

    Still waiting on an answer. If it is what you think that is OK. If you have sources to back up your claims please share them.
  17. safe

    safe Active Member

    Most of the people I've interacted with both on electric bicycle and gas bicycle sites have been older. So far I have not interacted with many people who are young.


    Historically things like BMX were more or less organized by adults for the children. Without the adult element the sport of BMX would have remained as something that only a few kids did with their banana seats and high rise handlebars. Bicycle shops needed to get into the sport (BMX) and sell things that kids wanted so that the selection improved. It was really necessary for the adults to see value in the sport before it would grow. (it had to be accepted by the parents) I used to work at a bicycle shop back in the 1970's so I saw the sport grow from the begining.


    I would not be surprised if there were a few people in each age group that are into motorized bikes, but so far all I've come into contact with is older people. (like myself... at near 50) If there are 16 years olds that are excited about motorized bikes I haven't heard much from them.
    Last edited: Jun 26, 2010
  18. Yeah, we were discussing a product with different battery "levels", so the costumer could buy the cheaper battery and upgrade later, without any modifications to the bike itself. So, as long as the batteries are the same voltage, there would be no problem creating a situation like that?
  19. Stan4d

    Stan4d Banned

    Thank you for telling us that you are using your own interaction to form your opinion. I only have to say that demographically teens will not interact with 50 year olds, and blanket statements about MBc membership should be avoided.
    I will now let the thread get back on topic. Pardon the interuption.
  20. safe

    safe Active Member

    The Thundersky cells were specifically designed to imitate the SLA's in both size and voltage. It wasn't an accident that it is this way. Normally there are many issues that crop up when you try to switch chemistries because the size is different or the combination of subcells is different so the voltages end up slightly off.

    Many other entry level ebikes use two 18ah SLA's as their entry point. The Thundersky's allow you an upgrade path for the battery without you having to do anything. It's sort of the "no brainer" solution.

    The cells are 3" wide in their thin direction and the ideal place to put batteries is in the middle of the bike between the legs of the rider. This requires that the frame can handle it and that's rare.

    Most ebikes DON'T do a good job of design and place the battery hanging off the rear end as a sort of rear baggage pack. This produces really bad handling and if you are using a hub motor it amplifies the tendency to break spokes.

    The center of gravity of a bicycle is in the middle of the bike. The closer you get the batteries to that center point the better.


    My avatar is of my newer bike and those are NiCads in solderless tubes. From a performance standpoint the (gray) battery is perfect right there. In fact, I'm considering getting two Thundersky cells to replace my NiCads and I'll mount them in the same spot. I've ridden that bike for maybe 20 miles and it handles great, but I've been stuck trying to figure out the best motor for it. (many technical problems are holding that bike back)
    Last edited: Jun 27, 2010