Alien 20" +Speed D7 What's it like as a "moped"?

[torrent99]

Hi,

I've been lurking around for a couple of weeks and thought it was about time to post.
I haven't got an e-bike yet but my plan at the moment is to get a Dahon Speed D7 and convert it with an Alien 20" kit or Tongxin.

The reason to have an e-bike is to allow me to cycle again with my very dodgy knees.

My hope is that with this I get a bike that I can pedal when I'm able, will let me not pedal if I can't, and in an emergency take it on the Tube.
(Foldability will let me keep it securely in the flat or at my desk. I plan to walk it up the notorious Highgate Hill)

The one thing I'm concerned about is how this bike will handle with motor only (no pedalling). Would it be able to do a standing start? How fast might it go on the flat? I'd need this for days when my knees wouldn't let me pedal (like the last 2 weeks for instance).

My work route is very gently downhill in the morning and the reverse in the evening.(Apart from the very steep Highgate Hill end which I expect to walk up!)

Cheers

Steve

 

[Tiberius]

Hi Steve, and welcome to the forum.

Ambition should be made of sterner stuff. If Highgate Hill is on your regular route, then you should be looking at an e-bike that can get up it. If you don't aim for that, then you are throwing away one of the main benefits of e-biking. You will also get us heroic wilderness types teasing you about being a metropolitan pansy. (I can say that because I used to live in London.)

Before you settle on a particular bike, why not check the gradient of the hill and post the result on here. I'm sure lots of people will then be able to advise you. You can work out the gradient by actually measuring it with a spirit level or by reading data off various online or paper maps.

Nick

 

[torrent99]

Well a quick google says that in it's steepest parts it's a 1 in 5!

Actually Highgate Hill is at the end of my route (my flat is at the top!).
So I'd probably walk that bit just to get the exercise (My knees actually respond better to walking than cycling), + there might be a toddler strapped to the back.

>>You will also get us heroic wilderness types teasing you about being a >>metropolitan pansy. (I can say that because I used to live in London.)
Actually I moved to London when my knees died to get me away from the temptations of real hills...now I do white water kayaking instead.

I'd say the max gradient I'd normally expect it to do would be about 1 in 40 (if I'm reading the streetmap correctly), so pretty flat.

Given my knee situation there's a good chance I'll need to use moped mode quite frequently...

Cheers

Steve

 

[Tiberius]

Hi Steve,

1 in 5 would be heroic wilderness standard, but it doesn't have quite the same atmosphere in an urban environment. My house is also at the top of a hill, which is nice, but the wrong place for an e-bike expedition when you return with flat batteries.

1 in 5 can be done, but not by all bikes. If I were in your situation, I would still be looking for a bike that could do it, and that means:

Low gearing / small wheeled hub motor,
Drive through gears system, or
Excessive power.

Nick

 

[torrent99]

Hi Nick,

Thanks for your help...

>1 in 5 can be done, but not by all bikes. If I were in your situation, I would >still be looking for a bike that could do it, and that means:

>Low gearing / small wheeled hub motor,
So something like the hub for a 26" wheel built into a 20" wheel?
...very slow on the flat.

>>Drive through gears system, or
E.g. the Cyclone?
Can't fit it on a folder...

>>Excessive power.
Ahhh, someone on EndlessSphere has converted a Dahon with a 500W motor....goes like the clappers apparently!
However, it is VERY heavy which might preclude me being able to get it from the street to my desk (leave an electric folder locked out on the street in London?!?) I'll be looking into it though.

(BTW Is it me, or is endlesssphere inhabited by DIY speed junkies?)

Cheers

Steve

 

[Tiberius]

(BTW Is it me, or is endlesssphere inhabited by DIY speed junkies?)

Could well be, though it may be as much to do with the US preference for throwing more horsepower at the problem rather than indulging in refined design work.

The US limits are 750 W and 20 mph against the EU ones of 250 W and 15 mph. There seem to be more DIYers on ES and more buyers of ready made bikes on Pedelecs. All these things will create the impression that ES posters are more into speed than Pedelecs ones; then the difference between the two forums becomes self-reinforcing.

Nick

 

[Tiberius]

PS, Steve, I just looked up the bike you are talking about:

You have a really good space there for the battery. Here's what I did with a folder:

That's a Crystalyte motor in 26" wheels, and very much in the ES mould. It will eat 1 in 7 hills. I don't have any 1 in 5 roads locally, but its been up some very steep off road mounds. With 20" wheels it would climb anything.

Full story here Re-V Integrated Transport Solution

Nick

 

[torrent99]

Errm, yesss very ES. Forgive my lack gusto here but... unlikely to fit on the tube is it?!? + I don't have the light plane either! ;-)

I'll have another look at crystalite though. But to answer my original question, do you have any experience of the 20" Alien kit (24V 250w Bafong) on the flat?
Or would a 36V Tongxin be more appropriate? (concerned here that the rollers might slip on a standing start)
(If it'll reach 12-15ish mph on the flat that's fine for me. If it crawls around at 7mph it's a bit too slow!).

Cheers

Steve

 

[Mussels]

I was looking to see what gradients I go up so I may be able to offer a comparison, I didn't find out the gradient but I found this:

A fellow cyclist blows past me at a set of traffic lights, as I suck hard on my bottle, almost desperately, before the attempt on Shooters Hill. I have a target now, one that superceedes simply broaching the crest of the hill and I leave the stop line with a grunt, forced from my throat as I devote every fibre of my being to catching and passing this other lycra clad machine.

He is not my enemy, but I wish to damage his pride, a primal hunting instict sharpens my focus and a cool intensity grips me. He has hit the steepest section and is working hard, I shift up, rising out of the saddle into a full sprinting climb. Air rushes down my throat and through my nose, jaw hanging slack. Wide open. The hill is steep now, my arms and fingers ache from pulling on the bars to counterbalance my legs pulling and pushing at the pedals, symutaneously, in an unbreakable rhythm. I can feel hot, sticky drool escaping my limp mouth and lolling tounge, but I have almost reached him now. He hears my approach, the sucking of air into my lungs and the hoarse hush of it being expelled, but he cannot respond. I pass him and continue my assault, mind forcing now deadened limbs to continue the sprint as the camber becomes level.

I can't wait until he tries that with me, the other guy probably didn't change his pace at all for this idiot.
That has to be a good reason to ride up Highgate hill, so other people like this can wallow in their self pity when they fail and lose lots of points for being overtaken by an electric bike.

 

[Tiberius]

Errm, yesss very ES. Forgive my lack gusto here but... unlikely to fit on the tube is it?!? + I don't have the light plane either! ;-)

I'll have another look at crystalite though. But to answer my original question, do you have any experience of the 20" Alien kit (24V 250w Bafong) on the flat?
Or would a 36V Tongxin be more appropriate? (concerned here that the rollers might slip on a standing start)

I have experience of the 36V Bafang. Nice compact motor available for front or rear wheel, the two I have are 4.3:1 gearing. The Crystalyte is not geared, no freewheel and is heavier - probably more suited to rough-hewn, outdoor ES types than hopping on and off public transport (whatever that is).

I have no experience of the Tongxin. One thing claimed for it is the low resistance in overrun, but I found the Bafang is pretty good for that too.

Nick

 

[torrent99]

Nick thanks for that info.

BTW Where does the rotational speed of these things get set? In the controller? I.e. what tells the controller that you have a 20" or 26" wheel so it knows how fast you are going (from the hall sensors)?

I suppose where I'm going with this is, if I were to get a 20" kit from Alien, what if were actually just a 26" kit mounted in a 20" wheel. Then it'd go very slow wouldn't it?

Cheers

Steve

 

[Tiberius]

Steve,

The absolute max speed is set by the motor no load rpm at the battery voltage. Obviously that is also dependent on wheel size.

The controller may limit at a lower speed - to comply with the 15 mph rule. If so, it will have to be programmed with the wheel size. I don't know how that is done, you'll have to ask Alien.

Actually its possible that with 24 V and 20" wheel the max speed could be around 15 mph anyway. Depends how the 24 V version of the motor is wound.

Nick

 

[Boby]

Hi Nick,

>>Drive through gears system, or
E.g. the Cyclone?
Can't fit it on a folder...

Steve

I saw Dahon with Cyclone kit. It works. Pictures to be delivered probably on Monday.

I already had a short ride. It works silent, has a free wheel. Potential problem may be the replacement of the original chainring (in Dahon usually 52T) with a chainring delivered by Cyclone (44T). This change may make the bike undergeared.

Cyclone kit must work in folding bikes. Even kit installing process is shown on a folding Giant: Electric bicycle DIY kits kit e-bike DIY kits kit Electric bicycle DIY kits kit e-bike DIY kits kit Electric bicycle DIY kits kit e-bike DIY kits kit

Bob

 

[torrent99]

I saw Dahon with Cyclone kit. It works. Pictures to be delivered probably on Monday.

I already had a short ride. It works silent, has a free wheel. Potential problem may be the replacement of the original chainring (in Dahon usually 52T) with a chainring delivered by Cyclone (44T). This change may make the bike undergeared.

Cyclone kit must work in folding bikes. Even kit installing process is shown on a folding Giant: Electric bicycle DIY kits kit e-bike DIY kits kit Electric bicycle DIY kits kit e-bike DIY kits kit Electric bicycle DIY kits kit e-bike DIY kits kit

Bob

Interesting.... I'd seen some posts here saying that it wouldn't work, due to the smaller length of chain between the cranks and cassette, which means that with the additional fixed point of the motor that there's not enough play in the chain for the derailleur to work. Obviously not!

Wow! Just seen the Cyclone equiped A-Bike! R2D2 strikes again!

Cheers

Steve

 

[Boby]

When installing Cyclone kit you must add several rings to the chain (not many-since the chainring is smaller).

I consider Cyclone kit for my Dahon mainly becasue of its weight (motor ~2kg) and acceleration.

I am not afraid of the chaindrive noise. I saw Dahon/Cyclone and it was silent. Is Cyclone chaindrive system really stronger than hub systems (even geared)?

 

[torrent99]

When installing Cyclone kit you must add several rings to the chain (not many-since the chainring is smaller).

I consider Cyclone kit for my Dahon mainly becasue of its weight (motor ~2kg) and acceleration.

I am not afraid of the chaindrive noise. I saw Dahon/Cyclone and it was silent. Is Cyclone chaindrive system really stronger than hub systems (even geared)?

The advantage that the cyclone has over hub systems is it can use the bike's gears i.e. like in a car to get the best efficiency at any particular speed.

Hub systems with gears basically have only one gear!

The disadvantage of the cyclone I believe (for my uses anyway), is that it always needs you to pedal. (Plus in my opinion it's really ugly!)

Cheers

Steve

 

[Boby]

The advantage that the cyclone has over hub systems is it can use the bike's gears i.e. like in a car to get the best efficiency at any particular speed.

Hub systems with gears basically have only one gear!

Steve - do you use Cyclone system? Did you compare it to motor hubs (acceleration, climbing)?

I was teached that electric motors generally do not need gears. And neither my vacuum cleaned nor a washing machine has gears. I mean I do not know whether using gears is really such a Cyclone kit advantage. Any comparison of motor hubs to Cyclone system would help.

I know that direct drive hub motors accelerate slowly. This is the result of small torque. But geared hub motors often have big torque - do they accelerate faster? Maybe geared hubs performance is similar to Cyclone kit performance.

Hub systems are simpler. Cyclone system affects rolling resistance when man-powered. It is my concern.

Cheers

Bob

 

[Mussels]

I was teached that electric motors generally do not need gears. And neither my vacuum cleaned nor a washing machine has gears. I mean I do not know whether using gears is really such a Cyclone kit advantage. Any comparison of motor hubs to Cyclone system would help.

Electric motors have optimal speeds and outside the working range performance is dented. Vacuum cleaners are geared through the fan blades and washing machines are usually geared through the belt drive but because the load is carefully controlled they don't need a range of gears. On an ebike it would be great to get maximum performance at any speed between 0 and 15 mph and the best theoretical way to achieve that is through variable gearing.

 

[flecc]

To correct a false impression from above, a Cyclone system doesn't always have to be pedalled, the kit includes
a chainwheel with integral freewheel that permits the motor to drive without the cranks being rotated.

Equally there's a freewheel within the motor chain drive sprocket so the system adds hardly any drag and if
properly set up will have much less drag than a hub motor. This much it has in common with the Panasonic
system, though of much lower quality.

Drive through the gears is fundamentally better at using the power of these motors in mixed territory, but it isn't
more efficient on e-bikes. The reason is that e-bikes spend a very high proportion of their running time at or
near to their maximum speed, which in turn is quite close to the point of maximum efficiency of a hub motor.

By contrast, a drive through the gears system spends most of it's time in top gear when at or near maximum
speed, which in bicycle hub gears is a point of low efficiency, typically losing 10 to 16% of the motor power.
.

 

[torrent99]

To correct a false impression from above, a Cyclone system doesn't always have to be pedalled, the kit includes
a chainwheel with integral freewheel that permits the motor to drive without the cranks being rotated.

Equally there's a freewheel within the motor chain drive sprocket so the system adds hardly any drag and if
properly set up will have much less drag than a hub motor. This much it has in common with the Panasonic
system, though of much lower quality.

Drive through the gears is fundamentally better at using the power of these motors in mixed territory, but it isn't
more efficient on e-bikes. The reason is that e-bikes spend a very high proportion of their running time at or
near to their maximum speed, which in turn is quite close to the point of maximum efficiency of a hub motor.

By contrast, a drive through the gears system spends most of it's time in top gear when at or near maximum
speed, which in bicycle hub gears is a point of low efficiency, typically losing 10 to 16% of the motor power.
.

Thanks Flecc for correcting that, although I would say that from the design it can easily be seen that, if the bike is being driven by the motor it follows that the user MUST be turning the pedals at the same time (if not inputing much power). This is different to a hub motor design where the two power systems (human and motor) are more or less independent.

Interesting about the relative efficiencies though. I suppose this means that for a Cyclone you must use the gears in a very different manner to what you'd expect for a manual bike. Of course this problem comes because the two power systems are interlinked but have different gearing requirements, so ideally you need two independent gear systems for the human and electric power systems.

Cheers

Steve