Electric Bicycle

[garygadget15] in the UK has an interesting youtube page showing an electric bicycle. On his page titled, saving money the “green way” he has replaced his commuter car with one of these electric bikes. He then videos the commute with both to compare the results. The DIY electric bicycle kit he uses is made by Cyclone comes in multiple wattage’s ranging from 180 watts to 1500 watts where they do a great job of showing the conversion steps. They’ve got enough detail that you could fab your own from salvaged parts if you felt like it.

31 thoughts on “Electric Bicycle

  1. Don’t get caught by the fuzz!

    That wheel looks like it’s going way faster than 15mph, the main legalities of electric bikes in the UK are that they’re not to power the bike above 15mph (if you want to go faster than 15mph you gotta pedal faster) and the wattage of the motor must not exceed 200watts, in Europe it’s generally 25kph and 250watts but I think one or two countries have different laws.

    Nobody to my knowledge has been stopped on an electric bike because they were going too fast, I discovered a few months ago I could derestrict the throttle on my Urban Mover UM36, allowing me to get up to 20mph along the flat without pedalling (easily going over 20mph with throttle+pedalling and no extra pannier weight), normally the thottle was limited to 10mph, whilst pedalling alone the motor gives you power up to 15mph.

    I can understand why people want to have faster, more powerful electric bikes, it’s really a lot of fun being able to go 20mph+ without feeling like you’re doing a stage of the Tour De France, I just don’t want anyone on one to get caught by the fuzz for being stupid and then ruining it for everyone else who have unrestriced ebikes – so cycle safely!

  2. haku:

    The speed of the wheel when it’s spinning freely really has very little to do with the speed when under load.

    For general interest, here in Ontario the limit is 32 km/h and 500 watts.

  3. lifepo4 batteries are fantastic for some applications. They’re the ‘safe’ and ‘reliable’ lithium chemistry, at the cost of lesser energy density w.r.t. mass and volume. There’s at least one manufacturer who’s working on improving that.
    For deep cycling they’re fantastic.. I’ve heard anywhere from 1000-2000 full cycles before you reach 50-75% original capacity, depending on what marketing you read ;)
    This design makes me want to make a bicycle “series hybrid”, where you pedal into a generator, which outputs electricity to a battery or a motor. Then you just pedal at whatever speed you want if there’s still stored energy.

  4. Everyone asks about pedaling to recharge the batteries on hybrid bikes. Yes, it can be done on models with regenerative braking (though, not the cyclone), but Yuck! It is no fun to ride with extra drag. If you feel the need to generate electricity with your legs, set up a pedal powered generator in your living room, but don’t expect it to alter your carbon footprint one iota. The environmental cost of any extra food you eat will more than offset the benefits.

    Regarding the Cyclone conversion: The motor is mounted too low, making it very vulnerable. The lack of a bomb proof chain guard is a serious hazard. I’m not impressed.

    The easiest way to convert a bike yourself is with a hub motor, which replaces a regular wheel. Bionx makes a complete kit that is highly regarded. Crystalyte motors have a similar reputation, but require you to supply your own battery system. There are a lot of bargain motors from China, but it seems you get what you pay for.

    As for batteries, there are several adequate options, but no clear winner. I expect to see some substantial improvements in the next 5 years.

  5. @ Brian re:haku

    Normally you would be correct, but if the electric assist shuts off at 15mph you would have a lot more trouble holding 20mph.

    I don’t think you fully thought out the hybrid human-powered nature of the bike (unless that video had some explanation I don’t know of, I don’t have audio)

  6. Most places in the states the cops tend to leave you be on an electric bike so long as you don’t do anything stupid.
    The kind of stuff you have to do likely also will get you in trouble on even the non electric kind.
    The police where I live even tolerate those mini bikes and gas engines on bicycles so long as they don’t cause problems with traffic.

  7. I went to the 2nd day of a 2 day electric bike event in Wales earlier this year: http://www.tourdepresteigne.co.uk (I’m no.21 in the photo gallery, only one main pic of me at the bottom of the last page)
    the big event of that day was the 1 hour rally through the small town – which was very hairy at times because we were going through a churchyard whilst people were still using the church!
    I decided to ride with the 15mph speed restriction on because last year the road-legal winner was also on a UM36, but afterwards I wished I’d derestricted it (simply by unplugging a wire sticking out the controller) because most of the time I was going faster than 15mph to try and keep up with everyone else and that meant the motor wasn’t giving any extra boost, in fact it was having the opposite effect because I was pedalling against the motor (effectively in dynamo mode).

    Some of the riders on non-road legal bikes had special gearing setups and were easily achieving 30mph, lapping me several times by the end of the race.

    @brian, my derestricted UM36 tops out at 20mph on the flat with the throttle only because the motor won’t spin any faster, the bike shown in the above video has the motor powering the wheel through the gearing system which means it can go faster than a fixed geared motor (ie a hub motor like the one on my bike)

  8. Haku, racing and transportation are two different things :).

    Why does the hub motor have a fixed top RPM? That must be a limitation of the controllor/windings/permenant magnets/batteries, as theoretically a brushless doesn’t need to have an RPM limit.

    Cool, I wonder if you could use a cheaper motor and a lead-acid battery instead, but the controller is still an expensive item I suppose.

  9. nubie: All electric motors have a top speed for a given supply voltage. For brushless hub motors that speed is theoretically their Kv rating multiplied by battery voltage. Above this speed, the motor’s back EMF exceeds the driving voltage, preventing the motor from drawing power.

    Increasing the top speed reduces low end torque. Chain drives with multiple gears are generally thought to provide better torque with good high speed performance, at the expense of complexity and more stages for mechanical losses to add up.

    Cheap motors tend to be bigger, heavier, hotter, less efficient, less reliable, and lower power. You can always find a motor that costs less. The notable thing about these motors are the availability of high power (1500 watts = 2 horsepower!) in complete packages at low prices. Lead acid batteries work OK (cyclone even sells them) though they are heavy, lose capacity quicker, and contain lead which *must* be recycled.

    Lastly, I followed the links before “knocking” the product. I stand by what I wrote. If you want to build an ebike with the motor inches off the ground I wont stop you, but please try to add a better chainguard.

  10. seems like the motor wheel can not run free on this system. Which means the pedals will have to turn when the engine is running. (no free run, you’ll have to move your legs all the time)
    Plus, in the other way, it seems difficult to pedal without the motor running as you’d need to go against the motor resistance. This means it would be exhausting to go back home once the battery has run out out of power…

  11. The laws revolving around electric bicycles are actually quite a hindrance. It appears that, in my state anyway, an electric two-wheeled vehicle that can go faster than 20 mph is simply not street legal. It doesn’t meet the requirements for an electric bicycle, and it doesn’t fit the rules for a moped, either. This means that the only electric vehicles you can find are ones that are too slow to be suitable for riding in traffic.

  12. nubie: ah, I see my mistake. I hadn’t taken into consideration the fact that the controller is supposed to cut out at 15 mph, and so if the wheel is spinning faster then it obviously didn’t (whether the wheel is pushing a person or not). OTOH, the speed sensor on the bike in the video could be on the front heel (which is not spinning).

    orv: I’m not sure what you consider suitable for riding in traffic, but most cyclists consider 12-20 mph plenty fast enough.

  13. Just a little info for those interested, the motor and the pedals have freewheels fitted so do not turn with the motor and you can pedal without turning the motor. The video of the wheel spinning was with no load so is faster than when under load. Also the 15.5mph UK limit is derived from the European law (or the other way around!) but generally either a 250watt or 200watt (350 watt for a tricycle) average rated motor is ok, top assisted speed is 20kph (15.5mph) the bike motor and batteries must not weigh more than 40kg and only 14 year old and above are allowed to ride them, but UK law allows for an average user speed , so if you weigh 9 stone and are 14 years old you will travel a bit faster than someone who weighs 25 stone, providing it is designed for an average user the law allows for a degree of variance. And has speed restrictions do not apply to cyclists in this country you can pedal has fast as you are able….The cyclone was my choice (over the Wisper) as it drives through the gears, in a lower gear it allows me more torque and climbs quite steep hills at a very reasonable 15mph but in top gear it will travel at 22mph depending on wind etc. this allows me to add to the motor assistance with pedalling so I can keep up with normal traffic flow (very much like the newer Panasonic bikes out now but a lot cheaper). The gearing dictates the speed more or less. With hub motors it’s the controller but again the rider’s weight and conditions vary the speed somewhat, though I would add that Hubs seemed to assist you to 15mph and added drag when you want to pedal faster, the cyclone just freewheels when I pedal faster than its maximum speed. As for the motor position this is a compromise, low down and central to the bike, makes for a better balanced bike but also is in a position to be splashed, though I have not managed to knock it yet, as it seems to be high enough to be out of harm’s way. A hub motor is a heavy piece of kit and fitted to a front wheel can feed back through the steering (not very nice), in the rear wheel it can make the bike back heavy and not very nice in the wet. Ok not that little a reply – but anyone interested in an alternative commute to work I would highly recommend you get an electric bike, but with a very bright yellow coat and a load of flashing lights and a book on cyclecraft, and just keep on believing those motorists really just did not see you!!

  14. i’m curious, what effect would it have to connect the pedals and motor through a differential? wouldn’t it essentially add the two inputs? you could achieve higher speeds/more torque this way.

  15. Improved technology is creating longer-lasting batteries with extended life and range – all while prices continue to decrease. Electric bikes are becoming a more viable option than ever before and there’s been an explosion of DIY kits and new electric bike models.

    Other posters have mentioned the laws that limit the speed of electric bikes to 20 mph – but this also allows you to avoid paying for insurance, registration and all the other fees associated with motor vehicles. It’s not very hard to upgrade a kit to do over 20 mph – and law enforcement is probably not going to know the difference if you’re going 20 or 30.

    Either way, electric bikes are a great way of getting around – and saving money! Here’s a great place to find more information about electric bikes & bicycle models >

  16. Nice contributions from everyone, this forum is a blast!
    Some people miss the whoe point of an electric bike though. These thinge are primarily fo ‘assist’ and not sport racing, so I wonder why the avarice towards more amd more power.
    The essence I think is to weave in and out of trafic and get to your destination without breaking much sweat.
    Any motor that runs faster than you can peddal is simply running too fast for your own safety let alone the law.
    Im working on my own bike but I’m missing the drive sprocket on the motor. Any idea where I can find a 9T 10mm D-bore sprocket for bicycle chain?
    I’d be glad to know.

  17. my wheel way slower then this when i use my hand to spin the wheel it stops quickly it dont free spinn many times like the front tire and my battery only last an hour on free peddling

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