Electric bicycle questions

Who has tried out the latest electric bikes?

A few questions:

  • Does the overall concept make sense if what you like is bicycling? Most of the bikes seem to weigh about 50 lbs., which I guess makes them super light compared to a scooter or motorcycle, but very heavy if you want to pedal them uphill.
  • Are they more or less fun on a 2-hour road ride than a standard road bike?
  • Do you actually get any exercise when using one of these?
  • Are they way better for mountain biking because you can maintain momentum even uphill?
  • Why do a lot of them cost more than a used Toyota Prius? (maybe that is an unfair question since there are non-electric bikes that cost more than a new Toyota Prius) If this were a mass-market product would they need to cost much more than the $600 that you’d pay for a good hybrid/city bike?
  • Why aren’t the big bike companies, such as Giant, Trek, and Specialized, leaders in this area?
  • Are they amazingly great for keeping up with a friend who is in killer shape and is on a non-electric bike?
  • pedal-linked or throttle control for the electric motor?
  • is there any point in having more than three gears once the electric assist is available? Why not ditch the low gears in favor of software that automatically adds electric power if the cadence falls while the rider is putting a lot of torque in? (maybe they are already doing this)
  • shouldn’t tandem bikes all have electric boost? Tandems are already crazy heavy and expensive.

It is sad that, at least for the weather-wimpy, we don’t have a long biking season here in Massachusetts (not long enough to justify a $3000 electric bike anyway!).


57 thoughts on “Electric bicycle questions

  1. I haven’t actually ridden one, but the Genze bikes get good reviews and are relatively light.

    My girlfriend had an electric bike that she almost never rode because, at 65 pounds or so, it was so heavy that even getting it outside was a pain.

    Do you actually get any exercise when using one of these?

    Not really. Which is I think their point!

  2. I have one. The primary purpose of the electric assist for me is to flatten the steep hills of San Francisco, I would never be able to bike otherwise.

  3. “is there any point in having more than three gears once the electric assist is available? Why not ditch the low gears in favor of software that automatically adds electric power if the cadence falls while the rider is putting a lot of torque in? (maybe they are already doing this)”

    From what I’ve seen, the range of three gear systems is very narrow. That is, there’s not much point to 3 speeds unless you don’t have any hills and you aren’t going very fast. If you run out of battery power and have to deal with hills, you might want the lower gears.

  4. In some areas, electric-assisted bicycles are banned from using bike trails and bike paths.

  5. Two years ago, I was shopping for a used bicycle fitted with one of those small gasoline powered motors, but couldn’t find anything in good condition. I then started shopping for a used 50 – 150 cc scooter, but couldn’t find anything in good condition. I ended up buying a used ’09 Kawasaki Ninja 500 for $1700 in excellent condition from a desperate female seller.

    Last month, on a trip to the Colorado Rockies, I spent an invigorating day downhill mountain biking! For $120, it included use of a premium mountain bike, all safety equipment, and an all-day lift pass. The ski lift takes the bike rider and the bike up the mountain, then it’s a thrilling 50-minute downhill blast – as fast as you want, no pedaling required. Plenty of groomed, scenic trails, beginner level to expert. Even spotted some deer, beaver, and fox! Can’t wait to go again!

  6. One way to start cheap is to buy a $200 front-wheel conversion for an existing mountain bike. Check Amazon and eBay. They need batteries, not included. Lead Acid will be cheap but too heavy, so I would spend the money on whatever the best battery is.

  7. Electric bikes are amazing. There are many Gootube videos of electric bikes hacked to go 50mph on surface streets & over 200mph on race tracks. Ordinary bikes can be fitted with hobby parts or stock electric bikes can be reprogrammed. It should be no problem for a PhD in EE with many millions of dollars from successful startup sales to hack an electric bike to meet any requirement.

  8. I am sold on electric bikes. I really enjoyed my Xootr scooter and XSkate when they were still working. The only reason why I am not buying a ebike is that if I get one it will keep me from riding my normal bikes and from using the motorcycles that I already have.

    Seems like an ebike is $1000+ from Alibaba or $1700+ when someone else imports it.

  9. Legally speaking, when you put a MOTOR on a CYCLE it becomes a MOTORCYCLE,not a bicycle (unless the motor is very weak), so many bike conversions are illegal. Bike conversions don’t have to be expensive. In China (and now in NY Chinatown so the Chinese takeout delivery guys don’t have to pedal) there are tons of bike conversions. They also sell kits on ebay. I can’t say how good these kits are but they are not that expensive. OTOH, they probably have typical Chinese (lack of) quality. The big weight factor is the batteries – lead acids are cheap but heavy, lithiums are lighter but more expensive. And the further you want to go, the heavier the batteries are.

  10. To answer some of your questions:

    – Yes, an electric bike is a lot heavier than a non-electric one. They are really meant to be used with electric assist. Riding an electric bike with an empty battery is possible, but feels heavy.

    – More or less fun? Depends on what you want. Get great exercise? use a non-electric one. Get some exercise, while also going really fast and/or uphill easily? get an electric one. The main target market for electric bikes are either older people for whom riding a non-electric bike would be too strenous, or commuters that want to commute by bike, but not arrive at work sweaty. In both cases you still get some exercise, but it|s easier and more comfortable. Also, using an electric bike to go on tours together with a friend who is fitter, but on a non-electric bike, would probably work great.

    – How much more expensive? Most electric bikes built by large manufacturers are sort of a regular bike with the motor and battery added. Those cost about 800 bucks more than a comparable non-electric bike. The really expensive ones are those that are built specifically to be electric, often with a larger battery and more powerful engine, more like a lightweight electric motorcycle than a bicycle.

  11. Here in the Netherlands, they’re popular with older folks and disabled people who have trouble riding a regular bike. This is probably a special case though, since biking is far more convenient for getting around most places here than driving.

  12. My wife has an electric bike. She loves it. The battery is removable, so you can use as kind of a normal bike. It works for hours (without charging.)
    She uses / turns on the battery on steep and long slopes. And when she cycles far (into the city, when her destination is far considering cycling there and then back later in the evening), and she is tired, she can use the extra power not to exhaust herself extremely.
    It costs around 1000$.

  13. Rob: That Copenhagen Wheel looks like kind of a bad idea. The battery rotates? That saves a slip ring but isn’t the idea always to reduce the rotating mass?

  14. It allows everything to be self-contained in the wheel. But yes, rotating mass is one of the worst kinds of mass. Are you going to go there today?

  15. The self contained concept sounds good but it’s ridiculous to have the battery spinning. And I assume it’s impossible to just swap batteries since they are built in to the wheel?

    I do like the idea of implementing the throttle wirelessly. If you could limit the wiring to just the connection to the battery it would make a electric conversion look less like a rat’s nest full of wires.

  16. Legally speaking (at least in Massachusetts), when you put a motor on a bicycle you DON’T get a motorcycle (as logical as that would be, lexically). You get a moped, depending on the power of the motor – see https://www.massrmv.com/rmv/license/7moped.htm for more details.

    If it meets the requirements, then not only is it not illegal, but it doesn’t even require a motorcycle license to drive it.

  17. Electric bikes in MA are just bikes until there is case law to say they are mopeds.

    In order to be a moped it would need to have a gas engine of no more than 50cc and an automatic transmission. If you get a ticket, just go say it has no automatic transmission and show your gear selector levers.

    They are not motorcycles because they have pedals.

    I have never heard of the police enforcing any law against an electric scooter.

    I had an electric skateboard in Cambridge forever ago and never had a problem. The police go after noisy things that run on gas.

  18. Four cheap 12v lead-acid batteries are $100 but weigh 30 lbs. They would be 4amp-hours at 48 volts and have a 5-10 mile range.

    A 15 amp-hour lithium battery would be $322 and a much better value due to the light weight. 50-30 mile range. I would consider this the minimal thing to consider.

    A 25 amp-hour battery would be $475 and have a 30-60 mile range. Seems like the one to get.

    A front-wheel conversion with 1000 watts is $210.

    So $700 will get you the kit and a good battery.

  19. As I read the Mass. law, electric bikes are not “motorized bicycles” (lacking an auto trans. and a gas motor) but they are “motorized scooters” which subject them to a whole different set of (stupid and archaic) laws. Whether cops actually treat them this way as a practical matter is a different question.

    One thing is clear – either motorized bicycles or scooters are supposed to have a top speed of less than 30 or 20 mph, respectively. Between 30 and 40, it is considered a “Limited Use Vehicle” and over 40 it would be a motorcycle.



    Since many electric bikes claim to go much faster than 20 mph, they probably fall into (and fail to meet the requirements for) some of the higher categories.

    I get the feeling that if you were to zip by a cop on an electric bike at 40 or 50 mph he would not look kindly upon it. Probably if you are going under 20 he won’t care whether you are pedaling or the motor is driving.

  20. Mopeds (motorized bicycle) regulation probably came up with the “must have automatic transmission” thing because if it had a manual transmission, they wanted it to be considered a motorcycle and that was the only other option at the time. Really, an electric bike is more of a moped than a scooter. That being said, an electric bike is small, light, and quiet – and can fly under the radar as a bike.

    If you want to follow the law exactly, then it is illegal to drive in the left hand lane except when passing. You then have to move back to the right-most lane. $100 fine. No police officer will ever pull you over for that. Not ever. Why? Because the judge would be annoyed and the officer would get a reputation for being a dick.


    This is what police regulate using “scooter” laws:


    I am sure they treat electric bikes as “bikes.”

    If you are going 40 and hit a kid, then they may look for some other way to charge you, and a civil suit is possible.

  21. I see that you can make a bike battery pack with 50 or more 18650 cells (that is what Tesla uses). You can buy those cells on eBay for $1 each. 13 of them will make 48 volts and 6Ah. So 5 sets of 13 (65 batteries or $65) will make a 48 volt 30Ah pack. I may have to make a pack. You can get brackets on eBay to hold them together like this:


    Or you can just duct-tape them together.

    I think my first project is to get my eXootr working again by making a new battery pack for it. When it died, there was no reasonable way to do it, but I saved the awesome scooter knowing that batteries would get better some day.

    A Pedelec is an electric bike regulated as a regular bike because it only assists when you pedal. So basically it makes any normal rider become a pro bike racer in terms of power. Some skirt certain laws that limit unregulated electric bikes to 20 MPH without human assist because they have a throttle that will take it up to 20 mph without pedaling, and then if you pedal (even not very hard), it will bring you up to 28 mph.


  22. If you’ve got a reasonable large frame that you like, take a look at the Bionix conversion packages: they’re not cheap, but they have gearless rear wheel hubs that connect to heavy but powerful batteries and a pretty smart pedal assist mode with a throttle and regenerative braking/charging capacity. I had their 500W motor laced into the frame of a Marin DS3 and I love it: it, and a toddler trailer, has replaced a car for commuting purposes and the daycare run. I’m consistently seeing ranges of 65+ miles on a single charge (overnight); there’s literally nowhere in my town we can’t go and get back from on this thing. Once moving, the throttle will have you up to 32 kph in half a city block; with full pedal assist, I have had to brake to avoid crashing into moving cars in front of me (you have to ride this thing much more like you drive a car).

    Whatever you end up doing, pay attention to battery placement: Bionix kits offer placement on the down tube; when I looked at Pedego, in addition to being a crappy frame, they’d stuck the battery out over top of the rear wheel, so the whole thing was stupidly unstable.

    I haven’t taken this thing off-road yet, and probably won’t, but it’s been hilariously fun to go zipping past road bikers and their Tour de France-inspired kit (spandex, SPDs, streamlined helmets) while you’re wearing jeans, a t-shirt, and not working very hard. No, you don’t get much exercise with this thing, but biking isn’t very good exercise anyway, so I don’t care about that. The bike makes you feel like a superhero — everyone I’ve lent the bike to has come away with a stupid, huge grin on their face.

    Bionix are not the cheapest kits out there — my 500W system cost me $2500, bike frame not included. But we’ve essentially parked a car, and in the Pacific Northwest it’s usable 11+ months of the year, so it’s worth it to us. YMMV.

  23. So if you can make a 30ah battery back for $65, why does the commercial one cost $475? This seems like quite a spread.

  24. 25Ah for $475 and that is the eBay price. It would be much more if you got it from a major maker. Yes, it does seem odd that the price has not crashed for assembled ones.

    What is more odd are guys buying worn-out recycled laptop batteries and testing each cell (out of hundreds) only to be happy if some are over 2000mAh when they can buy new 6000mAh cells for $1 each. I mean how little does one have to value their time to do that?

  25. While you can buy 18650s for $1 each, the desirable Panasonic ones (Tesla uses Panasonic) are $4 to $5 each. That may explain the wide difference in assembled pack prices.

  26. So, then what’s the difference between the $4 Panasonics and the $1 Chinese batteries? Are the $1 ones the rejects that didn’t pass QC at the factory? Will they catch on fire or leak in a couple of days/months/years? I understand that in a consumer product you are paying for packaging and advertising (I buy off brand alkaline batteries and they seem no different than Duracell even though they cost a fraction) but if Tesla could cut the price of their battery packs 80% it would save them millions , so why don’t they?

    I’ve seen some Chinese products (not batteries but cheap things like Dollar Store corkscrews) that superficially resemble the thing that they purport to be but are made out of such shoddy materials that they literally break after 1 use. So it looks like a corkscrew but if you try to actually open a bottle of wine with it the plastic screw (yes, plastic) shears off immediately.

  27. A few things. One is that you need “protected” batteries (have a circuit in them). They stop themselves from being charged when they are full. This is a must when you run them in series or else they can catch on fire when the weakest one is full and the others are not.

    Two – the no-name and/or fake batteries lie about their capacity. They will say 6000 mAh and will be 500 or 1000 in reality.

    The real Panasonic batteries that Tesla uses will claim to be 3400 and will be 3400. It seems like these are the ones that one should buy.

    Look at this – the guy bought all of the batteries under $3 each on eBay, and 100% of them were false-advertising. Many only 1/3 of their claimed capacity!

    Don’t be tempted to buy them due to the enticing capacity listing and price. It is a lie.


    Only buy batteries that are proven-tested:



    In summary, building a pack with 65 good cells would cost at least $400. You may as well buy a pre-made $480 pack (assuming that is also made with good cells).

  28. Here is one example:


    Says 5300 mAh.

    We know that 5300s have not been invented yet. If they were real, Tesla would use them and have a 467 mile range.

    So they are a scam. If you tested them, they could really be 400-500mAh and filled with paper as a filler with a much smaller cell inside the case (people have dissected cells of various kinds and found that).

  29. I just looked up the cells that I use in my flashlights. I thankfully have avoided the scams. I own Panasonic NCR18650A and NCR18650B. Two good ones. I remember not minding the higher price because I only needed two of them. But now I know one needs them even if they need to buy a lot.

  30. So in other words, Roberts earlier statement about putting together a DIY lithium pack for $65 is “no longer operative”.

    So to put together a decent e-bike, you are talking (minimum) $400 to $500 for batteries plus $200 – $400 for a motor kit plus say $300 for a bike, so $900 to $1,200 for starters. And that will get you a home brewed device and not a factory made integrated product.

  31. Correct. Expect to pay $4 per cell in packs of 50 for cells that are good.


    You can probably get them for less from Alibaba, with some risk of fakes and 6-9 weeks of surface shipping time. If you test them and they turn out to be fake, then you would have to pay return shipping to China. Lunacycle is a trusted source as far as I can tell as it was started by known people on a popular EV forum.

    A 15aH 48v pack would use $300 in cells. Buying a decent battery pack pre-made is $400 (good)-$800 (awesome).

    A front-wheel 1000 watt conversion kit is $220 (eBay/Alibaba) to $325 (LunaCycle) http://lunacycle.com/hubmotor

    Your price range for a total bike is right, but that is for a 1000 watt system with a battery 2-3x the capacity that many $2000 commercial bikes come with. If you were to buy a $1300 eBike in the US, it would probably be 1/4 the power.

    Seems like importing one of these (from someone on Alibaba) at the best possible price with shipping is a good option:


  32. It is commonly believed that cells under $3 each are made by taking discarded laptop batteries, opening them up, recovering the 18650 cells, and putting new counterfeit wrappers on them.

  33. Just learned that direct-drive hub motors are bad because they are about 15 lbs, large in diameter (bad for looks and rotational momentum), and have resistance when you pedal.

    One wants a geared hub motor. Cute, Bafang, and Tongxin are three brands of small 250 watts ones. The 250 size is light and is not likely to snap your dropouts – but is more of a power-assisant than something that can zip you around like a moped. I am probably going to go with a 250 watt geared front hub motor hot-rodded to 48 volts for 330 watts. I would still have to pedal this bike at times, I am told.

    But now I am sure that the $220 1000 watt direct-drive hub kits would not be what I want. Too much unsprung weight.

  34. I have decided to get this as my conversion kit:


    There are cheaper systems, but this is made with a double-wall quality wheel with stainless spokes, build by someone who cares. The company is in China, but the owner is from England, and is easy to communicate with. Online reviews on the EV forums are very good.

    The MAC motor is a high-quality version of a $600 motor that is considered the best, but for a much lower price.

    It is rear-drive, so is much safer (if it locks up), is compatible with having front-suspension. It will accept a freewheel up to 9 speeds.

    The geared-drive has a clutch, so when not in use you can pedal with no drag. The cheap conversions are all direct-drive, which have drag, weigh twice as much, and are much larger diameter – which both looks bad and also adds rotational inertia.

    The motor can be run at up to about 1400 watts, or even more. I will have him program mine for 1200 watts max.

    It comes with a premium programmable controller that is compatible with the same data system that MIT uses for experimental EVs. That option, which I am not getting, will even limit your power if a temp sensor inside the hub shows the motor getting too hot.

    This is about $500 delivered, and I have $400 into the battery, so I am at $900 for an awesome setup with 1200 watts and 960 watt-hour pack with an aluminum case and Samsung cells.

  35. $600 eBike:

    Mongoose 26″ Ledge 2.1 mtb bike $99, yescomusa.com
    48V 1000W rear hub kit $276
    Hua Tong 72V 40A controller $35
    10ah 24s lipo $275

    40+mph, range=45 miles @20mph.

  36. I changed my mind on the rear MAC motor and ordered another brand. I saved $200 by doing that, but now will have 500 watts instead of over 1000. The upside is the battery will last longer, I still have more power than Lance Armstrong, and the motor is smaller and lighter. The wheel probably won’t be as good, but it should be fine. I got two throttle types as not sure which I will like.

    Build list from BMSBattery (not including battery):

    Q128C-135mm 500W Rear Driving EBike Hub Motor Wheel
    $127.85 USD 1 $127.85 USD
    S12S 500W Torque Simulation Sine Wave Controller
    $34.00 USD 1 $34.00 USD
    S-LCD5 LCD Meter for S-Series Controlers
    $17.33 USD 1 $17.33 USD
    PAS–Pulse Padel Assistant Sensor With 12 PCS Magnets
    $6.90 USD 1 $6.90 USD
    Half Twist Throttle
    $4.20 USD 1 $4.20 USD
    HWBS – Hidden Wire Brake Sensor 1pcs
    $5.90 USD 2 $11.80 USD
    A Bag of 7 Meter Spiral Wrapping Bands
    $1.49 USD 1 $1.49 USD
    Thumb Level Throttle
    $4.00 USD 1 $4.00 USD
    $67.76 USD 1 $67.76 USD

    Total $275.33 USD

  37. Not to rain on your parade Robert, but wouldn’t you want a motor that is capable of matching PEAK watts and not average watts? This would give you the power that you need to climb a hill or accelerate. The racer guy’s peak watts were closer to 1,000. The average automobile that has a couple of hundred horsepower may only used a couple of dozen cruising at a constant speed on level ground. The rest is for more demanding activities such as acceleration and hill climbing.

  38. Here in Europe pedelecs (support pedaling up to 25km/h and then cut off) are becoming more and more fashionable even for younger folks. Also, since they do not need special insurance as faster (e-)bikes.

    I am currently shopping around for an ebike to use it for my daily commute of a few kilometers in hilly area in northern Italy. Since my last test drives (two years ago or so) I think that the bikes have greatly improved in terms on how smoothly the motor support blends into the normal pedaling. The dealer said that it is due to the improvements made on the sensors.

    The most popular (market share) are as far as I know are the components from Bosch Ebike Systems which are used by a large number of bike brands. They are also currently launching on the US market ( http://www.bosch-ebike.de/en/usa/home.html ) (Disclaimer: I am not affiliated in any way with Bosch).

    If you do not have a lot of time, IMHO it makes a lot of sense to buy a ready-to-ride bike and go with a supplier which is probably around in 5 years time when you may want to buy a new battery.

    However those bikes are not cheap. Depending on the other components you put in the bike, expect around 2000$ and above.

  39. Ok, after re-reading the initial post, here my 2 cents for your questions:

    Q: Does the overall concept make sense if what you like is bicycling?

    Yes, at least with the components from Bosch or Yamaha the experience is extremely smooth, as if you have wind from behind.

    Q: Are they more or less fun on a 2-hour road ride than a standard road bike?
    The biggest advantage is that you can easily keep 25km/h for a longer period of time, therefore your range increases a lot (compared to a normal untrained rider).

    Q: Do you actually get any exercise when using one of these?
    Depending on how much support you choose. If you choose zero support, your exercise is better than on a normal bike since the e-bike is a bit heavier. For that reason the better bikes still have a good gear shift.

    Q: Are they way better for mountain biking because you can maintain momentum even uphill?
    Yes, but for hard-core mountain bikers new products are currently in the making to provide an even better up-hill flow. They have more torque and probably stronger batteries.

    Q: Why do a lot of them cost more than a used Toyota Prius? (maybe that is an unfair question since there are non-electric bikes that cost more than a new Toyota Prius) If this were a mass-market product would they need to cost much more than the $600 that you’d pay for a good hybrid/city bike?
    A: Mostly because the Li-Ion batteries are still quite expensive. They use automotive-grade components.

    Q:Why aren’t the big bike companies, such as Giant, Trek, and Specialized, leaders in this are a?
    A: Because it’s quite expensive to develop the battery tech, engine and sensor package if you are not already experienced in this field. (E.g. Bosch is the market leader in MEMS which you will find now in every smart phone, also they have a lot of experience in electric drives, think power tools. For other suppliers, such as Yamaha/Panasonic dito)

    Q:Are they amazingly great for keeping up with a friend who is in killer shape and is on a non-electric bike?
    A: You bet, the engines put out around 250 Watts, a Tour-De-France-Pro can achieve around 300 Watts.

    Q: pedal-linked or throttle control for the electric motor?
    A: If you want cycling: pedal-linked. If you want throttle control, I would go immediately for a real road bike.

    Q: is there any point in having more than three gears once the electric assist is available? Why not ditch the low gears in favor of software that automatically adds electric power if the cadence falls while the rider is putting a lot of torque in? (maybe they are already doing this)
    shouldn’t tandem bikes all have electric boost? Tandems are already crazy heavy and expensive.
    A: This is a fair question, if you use a lot of electric support you can basically ignore the low gears. However, if you run out of battery it is not a bad idea to be able to get going with low gears.

  40. I think you see more pedelecs in Europe where they are required for legal reasons. In the US, we have 50 states with 50 different laws regarding what is permitted on the road, so e-bikes fall into a sort of grey and confused area. Especially with home built bikes, you can (at least until something bad happens) get away with faster bikes, no requirement to pedal, etc. as long as the bike looks like a bike and not a scooter or a motorcycle (it’s like the assault weapons ban – appearances count). Probably what will happen is that a few pedestrians will get run down by e-bikes (silently) going 80 kph and then the legislators and police will crack down, but for now e-bikes fly largely under the radar (as long as you don’t attract the attention of the police).

  41. There is a bike club that does weekly 35 mile rides at 19+ mph. I know I cannot keep up with that and would be much happier at 12mph, but I am pretty sure that if I use a Pedlec to ride with them, I will be ostracized. I would need one of these:


    Still, I am going to try riding with them. I will explain that I have it set up so that I will have to input over 100 watts on my own to maintain 19 mph and see if they buy it (if I do 120 watts and the bike does 150 watts, then that is 19 mph).

  42. I am surprised this is true, but all electric bikes are illegal in the state of NY.

    NYC only bans ones that have a throttle, but allows ones that require pedaling. Still, both kinds are illegal in the state itself.

    $1000 fine and they impound your bike.

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