All about DIY Electric Bikes, with Malcolm Faed
http://a4x4kiwi.blogspot.com.au
http://glowwormbicycles.com.au
Another HSC project from the Mater Maria College.
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http://a4x4kiwi.blogspot.com.au
http://glowwormbicycles.com.au
Another HSC project from the Mater Maria College.
EEVblog Main Web Site:
http://www.eevblog.com
EEVblog Amazon Store:
http://astore.amazon.com/eevblogstore-20
Donations:
http://www.eevblog.com/donations/
Projects:
http://www.eevblog.com/projects/
Electronics Info Wiki:
http://www.eevblog.com/wiki/
And we have a very cool looking electric bike here. unfortunately. Um Anthony who did it is? uh, not here. But M our electric uh, car and electric bike Guru is going to tell us all about it.
Hopefully? Yes. I certainly will. Um I assisted putting the bike together well, gave instruction anyway. I didn't actually have to do too too too much Anthony was very capable.
Cool. Um, it's an electric bike. the Uh I'll start at the back I guess the business end MH Uh, we've got a Uh 200 W uh. electric motor here 36v battery.
It's a brushless motor. The speed controller is internal to the hub, which is kind of neat because it means you don't have to find space for it anywhere else on the bike and it keeps it really well self-contained Is there anything on the right? Okay, so it's the wires. come in the other side and they're just cable tied up to the frame. I See it in the middle of the frame here.
He's built a burglar alarm or an anti- theft alarm I Guess it is for a pushy built up from a project. Um, you can see the ablea batteries there to power it when the Uh bikes. um, not being powered by the Uh by the main pack. Yep, oh it's a short circuits.
it's it's a JC Car thing. Yes, it is right. Uh, there's a tilt switch on the back of the battery pack. Uh, a Mercury switch.
So if the bike uh with the bike tilted as it is at the moment I think you'll find the switch is just tilt it a little bit in the off position. If you stand it up, the Mercury rolls to the other end and it uh and it closes a circuit nice and there. Where's the uh buzzer? Where's the screamer on it? Does it have a screamer? Dave I Don't know. Does it have a screamer or does it just not work? It just not.
It just doesn't under the seat? that's right seat I Remember now. Oh there we go. There's the screamer. There it is.
Yeah. I Love it. Anti- theft electric bike on the front. We've got a um Ole 10 wat LED 10 watt.
Nice. It's really really bright when it when it's on and you look at it, you've got stars for hours. So do you know what brand that is? Is it a Cre? Is it a one hung low cheapy from China Is it a I Suspect it's the one hung low cheapy from China right and that's powered through a little step down. Yep.
Converter here a switch mode converter. So it takes uh, anything, up to 50 volts input and steps it down to 12 vs. ready for the LED Got it. The LED has a constant current Source in the back of it.
How hard is it to take an existing bike and actually modify it to get a fully electric bike? Well when we um when I went to Dave's house to start assisting in the project, they had already started pretty much pulling the bike apart and I think he was riding by about lunchtime. Wow. really? Um, so it doesn't take very long. What does take time is tidying up the wires and making it look nice.
Got it? Um, my own bike is the same design and uh, I think I've had it apart about twice because I wasn't happy with how the wires were run right. Fussy about the details? huh? Yes, Yes, yeah, because you know, like you've got uh, tubing and all sorts of stuff along here. So I guess you want to, you know pride in your work? You'd want to. That's right, you know, could you hide it inside the tubes or something? Do people do that well? This bike has a few extra WI for the lights and and the alarm. Um, mine just has I think two or three running from the front so they just run parallel to the brake cables so they hide quite nicely under the frame. Yes, you could, uh, drill holes in the ends of the tubes and push the wires through y That would look quite nice. I Don't know what it would do structurally well might not be so clever, might end in tears. What's what's the legal requirements in Australia for Electri Watt: 200 Watt 200 WT Anything over 200 WTS It's classified as A.
It's not classified as anything. Actually, you can't make it legal. and it's not legal to ride on public places. Wow, You can't even register it as a motor, electric motorbike or something.
That, that's right. it doesn't comply with the appropriate Australian design rules. Great! So so anything above that is in no man's land, right? Interesting Segways are in the same position. They're not legal on public places either.
Oh okay, so technically you're not allowed legally allowed to ride a Segway That's right in. Australia That's right. Fail government, Another government Fail. Yes it is.
Yes, it is. Boy kill. Joys Yeah, so how much performance can you get out of a 200 watt legal limit at B 200 watt legal limit bike. This one will goes about 32 km an hour, right? Okay, so it's not super fast Hills and stuff like that.
Um I live at the top of a fairly steep hill and uh, I have to give it a little bit of assistance up the hill, but not much. Okay, so you can do combined Pedal Power as well as you have to. you have to. you have to.
I Love it. And how long would you? you usually get on a a battery pack of that size and weight? How? what sort of it's on a flat? You know, a reasonably flat. Yeah, if you believe the website I think it says something like 50 or 60 kilm on on the website. Um in reality I've been riding uphill in down Dale Um Sydney Terrain y It's realistically more like about 30 right? About half the yeah? figure.
Yeah, which makes sense. Yeah, some. um if you put lower or slicks on y of course that that helps pushing tires around. Yeah, that's right, cuz these are like mountain bike tires, right? So if you get low rolling resistance tires, you would.
What is interesting about these tires though? they are quite worn. Oh, he's got a is that? Uh, if he had full tread on here? Um, you've actually got almost continuous contact with the ground anyway. So if you're riding up and down, your rolling resistance isn't too bad. And what's the market like for these bikes? Are they selling commercially? Are they selling well? commercially? Do you know? CU You can buy commercial electric bikes fully? Yes you can. There's been quite a few, um, little shops pop up. some disappear. Yep. Um.
but they are specializing in an electric bikes. There's uh, a plug a mat's business name is Gloworm Bicycles. please do bicycles. com.au probably probably in in Sydney Um, uh.
so there's little businesses and industries popping up around it. There's also kits available online from on. eBay Where all good and bad come from? Yep, and from this manufacturer here, which is Golden Motor. Okay, so this is a Golden Motor.
It sounds very. uh Chinese One hung Loy certainly is. They've got agents here in Australia now or distributors in Australia now so hopefully you can save a little bit on the on the shipping right. and I'm sure their competitor is called Golden Lucky Happy Motorco I'm sure.
Beautiful! Are there any other uh uh things people need to know about building and electric bike? Not a whole lot. Well, I'll I'll Um I'll start at the start at the front now. Um, in the kit, you get a few different things. M You'll get uh two brake two new brake handles.
Being a brushless motor, this one does have regeneration and what's really neat about this is you can program it as well. Um, dial up how much or little you want. Um, there's a switch on each of these brake levers. What it will do is in the case of a brushless motor and controller.
Like this one, it will turn on the regen and turn off the throttle. If it's if it's on Mhm and it will, uh, on a DC type bike, it'll um, just cut the speed controller because you don't want to be fighting the speed controller with the brakes. Um, the mechanical brakes are all the same. The throttle is hiding under here.
Got it? I Prefer a thumb throttle like this one? Yep, because if you're pushing your bike around up and down stairs like I do to get out of my backyard, invariably end up twisting the throttle and the bike takes off on you, right? So it's actually quite a good. SA I Find the safer right? Yeah, that that would be embarrassing wouldn't you? CU if you are moving the bike around I Can imagine you would accidentally twist the throttle. and yes, it goes, especially when you're not used to an electric bike. Um, so we've got the throttle, the brakes.
yep, and the battery pack here that slides off the back and has a little charge port on the side of it, right? Oh okay, so you can take it away to charge it or remove it off the bike. Cuz really, the charger is probably worth the batter. Is Wor RCA connector? It is actually it is an RCA connector. How many amps can you get through an RCA connector? Well, I think it's about one or something.
Um, there's a Anderson plug on the front of the battery pack. Um, which is a nice quick disconnect. Yep, sweet. And you can slide the battery off the carrier off the back for charging or storage or just to prevent theft because it's probably the most expensive single component. Sure. I Think this one will be a 10, 10 amp, 30, 6 Vol I've already talked about the Hub motor having the speed controller built in. That's one of the advantages of a golden motor. Otherwise, you have to figure out where to put it.
Maybe down here or under here. Thats how physically big would a speed controller. The speed controllers are usually about right that yay big and that so they're not too hard to hide, but it just makes it a whole lot more compx. Sure, if it's built into the Hub and what about? uh, how hot would one of those get? What about Electronics Reliability in there? Would that be an issue like that was a concern? I Guess with the earlier models, but this Uh brand has been around for a long time now.
Okay, a few people have blowing up controllers for various reasons I don't really know why, but uh, but yeah, they're good. They're on to the next version now and they're still keeping the speed controller inside the Hub so they're obviously not having trouble with heat dissipation. And what happens if the controller blows? Do you buy a new one? or does it? Yes, it's um, it's a bit of a mission to pull the Hub apart from what I hear because you're fighting the magnets and the coils and everything inside. But once it's apart, it's um, oh, you can could service it in theory.
you could service it, pull it out, and replace it, and in fact, the circuit board on it is physically identical to the one that's external in a box. so you could order it as a spare part and refit it or Y or just delete the controller all together and use another one so you can use it as pretty just a normal bike. Do you have to disengage the anything? You can ride it as a normal bike so you just leave it switched off. Yeah, you just leave it switched off.
Um, with a brushless motor like this, there's always rolling resistance. Yeah, so it's a bit of a challenge to Pedal Okay, so it's fairly significant in ter ride if you don't use it. so there's a penalty there if you have an electric bike and you want to do it the old fashioned way. Yes, that's right.
That's one of the advantages of the little DC Hub Motors that are about that big. The little Motors spin quite fast through a planetary gear reduction and they also Freewheel so you can p it a lot easier. Got it? They do. They automatically free whe? or do you have to disengage? No.
yeah, they automatically nice and these you can't really disengage it can you? Not at all. It's all. it's all built in. It's all there.
it's one piece. And how much would a it cost to make a electric bike cuz you you built yours from scratch? Yes. Much like this. I Bought a frame from cheap frame from Big W It was expense right to have streamers and all on. Yeah, right. And the little clicker thing in the spot Um, and and the um so the was cheap. but the the kit I think at the time was about 1,200 shipped. Wow, Okay, right.
so they're not. It's not insignificant, right? Still, cheaper than buying at a shop right? And how much would they cost in the shop to get a fully built fully tested? I Haven't actually looked for a long, long time? Okay, look up Glow Bikes website Gl.com most likely or Google Thank you very much M My pleasure Dave.
already the way of the do do bird. I had the opportunity to buy one of these bikes at our local GoodWill Store. lead batterys are quickly being replaced with lipo. Even then the motor is highly inefficient. you can still buy them on line but they are really dump in the price. I would take care of that speed limitation problem. I am looking at an electric lawn mower motor as a possible DIY alternative if I did go with an electric bike. Its in my future. all I need is to attach a variable speed controller. can you imagine the speed I can get out of that motor.?
The strangest thing in Czech legislation is that the e-bike is limited to max 250W and pedelec system, and 25km/h max speed and in the opositeto it a bike with 1kw gasoline engine is still considered a bicycle as long as the motor is only "added" to it. Government fail
SHUT UP AND TAKE MY MONEY
No need to shut up. You make some decent points, after the initial trollish comment. 😛
I'm not going to add an extra few km to make use of them. And that's the problem. When they try and make things nice for recreational cyclists, they get more recreational cyclists.
On the direct roads, bicycles are seen as second-class. You can ride there, but try and stay out of people's way, okay. 😉
It's weird that the same doesn't seem to happen here. Maybe because we get so much rain here (Vancouver, BC) most people don't even see cycling as a realistic form of year-round transportation, and unfortunately a lot of the cycling infrastructure seems to be targeted more at recreational cycling, etc. It's all well and good to have nice long bike paths well away from the roads where you can go for a Sunday ride with the family, but when I need to get to work…
Anyway, I'll shut up 😛
The interesting thing is: even when limited to 25 km/h it still helps bike penetration tremendously. The netherlands are already the most bike-infested country in the world, and even though our landscape doesn't need pedal assistance at all, 15% of bikes sold are electric. The reason? Instead of just being a tool in fair weather, the electric assist allows the bike to be used in any time of year and any weather. It's convenience, just like the car is a convenience.
Ideally, you would do it in the controller firmware. Just turn on all of the lowside fets, and none of the high side.
No, it's a lot more drag than you get from the regen braking, because it's shorting all of the motors backemf, as opposed to just the few volts of boost that is typical on a regen brake.
It would be effective, though, and unless the guy's superman he's probably going to give up before he melts the wiring.
The tricky bit is switching it in a way that won't kill the controller if something goes wrong.
25km/h limit would do nothing, except to keep people from adopting a technology that might actually get a few more people out of their cars. Seems like one of those numbers that someone pulled out of his butt without ever having ridden a bike.
Here, people mostly ignore the silly law without consequence. The problem is that it is still illegal, and if you have an accident you can bet that the lawyers are going to point the finger at your un-goverened bike, even if speed wasn't excessive.
Wow. 25km/h. Hardly seems worth bothering with a motor at all. In most of North America it's 32km/h, and even that isn't really enforced. As long as you don't ride like a fool, nobody is likely to notice or care.
On my road bike I normally cruise faster than 32 on leg power anyway, so there's no point there. It's nice on my longtail cargo bike where I sometimes carry heavy loads to be able to keep it around 30 on the hills.
Cargo bikes aren't very common here, though, so I think a ….
Ah, well, here in the Netherlands (and surrounding countries) we have laws stating that electric bikes cannot go faster than 25km/h without being classified as a motor vehicle (and thus requiring helmets, insurance, all that jazz) so almost all manufacturers state 120rpm specs. So that is why I quoted those numbers.
And those 20W lights on my velomobile are really useful at high speed and unlit terrain, but even with the optics they blind oncoming traffic easily. I usually run them at 10%.
you wouldn't likely cruise at 120RPM. that's only about 24km/h. Presumably you would be doing about 32km/h where the motor should be in the 75% ballpark, which isn't too bad. Geared ones can be nicer and weigh a lot less, but also usually cost more, are noisier, and more complicated.
And no, on the road you don't need 20 Watts of lighting. I have high powered lights, and I'm usually running at 10% PWM to not be totally distracting to other road users. I'm sure his light is sufficient.
(continued) and honestly, the cost savings if any aren't that big. There is maybe a $100-200 cost difference between modern Bosch front hub motors and these chinese ones, which you easily gain back through the savings on the battery. And that is one of the primary reasons that you would never see golden motors on quality dutch e-bikes, they're all either brushless or agni-type really high torque dc (which is another story entirely).
To give some quantitative background to that comment: the golden motors achieve about 55-60% efficiency at 120rpm, 250W and the motor weighs about 8kg. Compare this to modern-day brushless motors (geared, so a bit more noisy) that achieve a bit over 80% efficiency at the same point *but* also have much better low-rpm torque and efficiency, and weigh only 2kg. That means that for a 500Wh-equiv battery you save 6kg on the motor and a bit over 1kg for the battery.
The point I was trying to make is that the parts he used are extremely out of date, it's nearly 10 year old tech now, and there are much more improved alternatives nowadays that universally improve on these so-called 'golden motors'. Even direct drive ones.
There is no question about different technologies having their tradeoffs but this is just unnecessarily big, expensive, inefficient and not really what a bike is about.
And to answer your last question: 20 watts! bit.ly / R9JB5b
Yes. Some motors have a freewheel in them so that they can roll without turning the motor, which is nicer if you're going to be doing a lot of unpowered riding. The disadvantage is that the motor can't give any regenerative braking either.
It's most common in motors that have a planetary gear reduction in them, since the amount of drag turning a geared motor could be much higher (since it's spinning faster). There's not really a correllation between freewheels/gears and brushes though. 😉
I do not know what "no freewheel" means. I do know hysteresis loss. Maybe you can explain "freewheel". Is it a mechanical disconnection so the motor is not turning?
I think you do want to be mean, or you would pick a nicer word than horrid.
direct drive hub motors are just big. Not much you can do about that. Different technologies all have their tradeoffs.
I have little doubt the led is bright. Sure he could get better brightness/efficiency with a brand name one, but how much power do you actually need on a bike light? Run it a little below rated current, and do some decent heatsinking and it'll work fine.
Basically, the magnets magnetize and demagnetize the stator poles as they pass, and absorb some energy.
You can still ride, but you definitely feel some drag. It'll make a road bike feel like a mountain bike on knobbies.
I'd estimate you lose 3-5km/h of top speed, depending on the magnets in the motor. Not a big deal if you run out of juice and need to finish your ride home at 25 instead of 30, but if it's something you wanted to do frequently, better to get a freewheeled planetary motor.
Then you wear your rain gear.
No, It's because the particular DC brush motors he's talking about have a freewheel.
The brushless hub will have drag mostly from hysteresis losses in the stator, because there's no freewheel.
Right. He's probably looking at specific motors. Brushed/brushless has little to do with it. It's more a question of direct drive vs planetary.
A planetary setup will be spinning the motor very quickly, and the drag is probably significant, so they'll add a freewheel.
Depending which way you ran the current on which wires, it will just rotate the motor up to 9 degrees. (1 pole)
If you live someplace dry, and there's no rust, you can usually separate the motor by removing the screws on one cover, and then holding the wheel by the rim and pressing the opposite end of the axle against the ground. The stator will pop out with the side cover, and you'll have the other side cover and magnets separate.
If rusty, try a gear puller. You'll likely bend the stator.
Since this was only my second year studying in Industrial Technology Electronics, I don't know whats new or old, I just get info from my teacher. The alarm and lights were both something that I could MAKE to show my work progress in the subject. Trust me the light is really bright. Just as bright as a car's light. Also with my time and budget, this was the best I could do. I am studying 4 other subjects, so it's a little hard for me.
Yeah look I am the student who made this. I actually wanted to do that, but lets be honest. I couldn't be bothered haha.