Determining electric bike range and hill climbing ability

[chazpope]

I don't think I am misleading in any way re the 350W power - I am merely stating a fact. What I mean by 'explains its great performance' is that the UK version may have a 250 nominal power but we don't know that do we. So it could well be the same motor power-wise with some or none fake modifications so that is can be called a 250W. This of course is pure speculation but is in line with the general opinion here that the quoted nominal is nonsense. Same as how the nominal power of Salisbury went from 180 to 200 and according to them it has been the same thing all the way - so there is a lot of sense in what I said I think.

coops this is what you said re flatness

flecc had previously said why the non-flat road makes the measurements worthless. Doing the test in both directions does not cancel error from a non-level surface, it increases it: you would be measuring acceleration and hill climb one way, and speed and downhill freewheel ability the other,

My take on this is that whatever power is required to go uphill is added to the bike power in going downhil. The average power consumption is the same as on the ideal flat, therefore any imperceptible gradient error will not have an effect on the result.

Please explain in more detail why you think this is not so ?

 

[flecc]

Oh dear, there you go again, making wild assumptions!

The Salisbury motor did not jump from 180 to 200 rating. It's manufacturer had a brushed nominal 180 watt motor that was intended originally and that was mistakenly published as being the current version on the Powacycle site.

In fact the Salisbury in the market had a more up to date brushless nominal 200 watt motor. They were two totally different motors as I previously advised, the 200 watt rated one being more powerful and justifying it's higher notional rating. When the website error was brought to their attention, Powacycle corrected it, as I also previously informed you.

I explained this in your first thread, but you said you didn't understand, even after I clearly explained further. There's a lot you don't understand, including when to stop bluffing. You clearly don't understand this subject or have knowledge of the bikes. I tried to help in my last post by advising you on gaining the necessary knowledge to speak on this, but again you responded with bluff and guesses as I've shown above.

Likewise, the US Sprint motor is not the same power as the UK version and since you lack any of the necessary knowledge of these, you should not make assumptions that it might be. That's what we mean by misleading.

I really do not wish to have a row, none of us do, but if you wish to promote your rational test idea, it's best to avoid pretending to knowledge you haven't got. In that way you'll have the attention of members on the idea, and not as at present, focused on your obvious bluffing, mistakes and persistence with them.

You got off on the wrong foot with me as a result of your curt and dismissive responses on your Salisbury motor type thread, but it's really time for you to learn from events after your negative experiences in this second thread.

I make mistakes too, and when I do and a member corrects me, I apologise and thank them for the correction, since I'm grateful for the opportunity afforded for me to learn more. There's nothing to be gained for me to just pretend that I'm right.
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[ITSPETEINIT]

Determining Range and Hill Climbing Ability

Chazpope
Junior Member Join Date: May 2007

(1)________________________________________
I believe there is a considerable body of ebike buyers who like me will be using the bike for commuting, shopping and other general city use (i.e. not hill climbing) All I care about performance-wise is how fast the bike accelerates and how fast it goes - so these tests would be enough for me to decide where to go. In fact I don't care about range at all - every night I recharge my bike anyway - simply because when the battery is full it goes faster, but that is me.
(2)
Hill climbing ability is of course important - so there is the valid question - would tests on the flat be indicative of the bikes hill climbing ability ? I believe they would be - because they reflect the bike 'power'. How well that will work is what we are discussing here - and hopefully we will get to the bottom of it, but not without experimentation I think.
(3)
re what you say of these 2 bikes - perhaps it would be so - but think of cars - does the 0-60 test reflect the car's handling and genaral ability to go round curves and uphill ? No, but still these tests are very popular. Hill climbing ability on a e-bike will always be a slightly fuzzy subject (because is is always to do with pedalling will always be affected by gears, the exact value of the incline etc.) and I am not saying that the overall enjoyability of a bike as a hill climber can be judged from these tests. However I don't think the tests would be 'misleading' as generallty they will reflect the bikes power which also drives the bike uphill. There may always be exceptions - if some special bike is designed to go up a 10% hill all the time its test would be off but I think not wildly off if you see what I mean.
(4)
I don't understand what evrybodys issue with non-flat is - if you do the test in both directions as instructed (and obviously take an average of the 2 measurements) the effect of incline would be cancelled wouldn't it?
(5)
Ian the ez sprint is rated as 350W nominal on non UK sites - this explains its great performance - and this will show in the test. If the Torq really gets to 100m slower than the Sprint then maybe it is less suitable for city use and at traffic lights when you expect not to be pedalling it hard - this will also come out in the tests.

Itspeteinit's contribution:

re (1): You have defined what you want from an e-bike. I get the impression (impression only because I have only ridden 3 models) that they are not really 'designed' at all (I feel idignation rising in the distance): they evolve from the components that are 'available'. Sure there is a drawing made so that these available parts will 'fit together' - but as for conforming to a predetermined objective I think not. Did eZee think "We have a great motor here ( the Torq motor), let's put it into a 20 inch wheeled folder, it will go up hills like stink" It does! But who said " We won't put any gears on it, it will mean having a wide frame at the rear because we cant put a heavy motor like that in the front of a folder".
Then another idea: "Why don't we put it in a MTB type bike, that will appeal to a largish market. Then, unrestricted (for the American Market), it will go like stink on the flat because it has 700C wheels. It will need a lot of rider work on the hills (let them ride Choppers) Of course, with the motor in the front wheel it will be a bit of a rough ride". "Why don't we put suspension forks on the front?" "Nah!".
So here's your e-bike Chazpope - its the Torq. I have not come across an e-bike at that price with those accomplishments (but a few out there are being hyped up to that standard - we'll see!. No need for road tests, the answers are on the Forum, in quadruplicate.

re(2): No tests on the flat will not reveal hill climbing ability. Back to the Torq - It's a dream on the flat (I'm talking speed here), but on hills, well, who or what are you? If you need loads of help because your personal wattage is low (Age, Health, Fitness) the help is not there unless you can do at least 10mph on 10% gradients. But I don't have to pedal on the flat or I can please my self.If I don't help it I can achieve 22 mph (subject to certain variables). If I give it the benefit of my 50 odd watts I can do, well about 22 mph.

re (3):
I was once a 'pure' cyclist, with luggage. I never found hills at all charming. Even given the promise that 'what goes up, must come down'. The losses riding up a hill (time/speed) are never compensated by that thrilling decent. My consistent prayer was "not another down then up: losing all that height: why don't they keep it flat?". Flat on a bike is easy. Hills anathema, especially on an e-bike with all that added weight. Unless it's the other kettle of fish that has a low geared motor. There's no legal embargo on motor gearing, only on motor power (on-road).

re(3):
This "all the time" introduces an element of speciality which is not relevant to e-cycling where ever it is carried out. In practical terms some hill climbing ability must be present (whether by accident or design). Nowhere is plateflat. With its limited legal power the ability to climb hills (motor gearing) will affect the other criteria of performance (maximum revs). It's what nearly everybody who writes on this Forum complains about. The nanny-state's interference in freedoms which precludes an e-bike 'doing it all'. But why should we worry? There's a plethora of e-bikes that will do 15 mph (the legal limit in the UK) on the flat and climb a wall (or nearly).
Flecc's 'Q' bike does all that and more. If we want to break the land speed record we are on the wrong machine. This whole discussion is academic and esoteric.

re (4):
The answer is in the above. Everybody's issue with non-flat is the gigantic difference between flat and hills. The downside does not make it alright for the legs and it does not make an average for science that is equal to the flat. Perhaps the Tour de France is a good indication: the difference between the climbers and the sprinters - on the hills and on the flat. Two entirely different sorts of 'engines'. The ability of one sort of cyclist in both disciplines is quite different.

re (5):
I've always thought of my Torq having good acceleration away from rest. Like the Sprint. On a head-to-head I don't know: have not thought about it.
But on a hill in Devon (8 to 10% x 1 1/2 miles long) where I had to stop often, to catch my breath and rest my legs, I had no troube in restarting. I was already in the lowest gear (39 inches - my modification). Open the throttle and put pressure on the pedals and I was 'flying' at 10 mph for a while until gravity brought me back home to reality. The Sprint would have fared better because it would not have given up at 8mph without me pedalling.

Now if only Isaac Newton had owned a bike! .
Peter

 

[chazpope]

peter

thanks for all the interesting comments.

you advise to read the forum for an idea of the bikes performance - this is all well but surely it would be easier to look at figures, and I appreciate that you also need to be aware what they mean. For example your experience with the Torq for whatever reason seems to be in some ways opposite to Ian's above ? You would think it is accelerating quite well from start while Ian kind of doesn't. If only we had a figure (test for this acceleration things would be put in better perspective.

I do not get yout point re 4 above - the question here is: 'when measurung speed and acceleration without pedalling on a visually imperceptible gradient (appearing as flat surface) - would it be safe to assume that doing it both ways and quoting an average would cancel the effect of this hidden gradient' (excuse the twisted description but that's what it is) I think my logic is ok and I explained why. Getting different figures would be an indication that there is in fact a gradient and maybe you can choose another testing spot, sorry if I got in geek mode here a bit


flecc

Yes you said that there was a mistake re Salisbury - but not in this great interesting detail. But I had 2 good reasons not to be so sure, and about that you still seem to have an axe to grind. One: my dealer told me that the Salisbury has gone up to 200 from 180. Two: long after it was posted as 200W on the website - Carl of powacycle told me it was 180W. When I pointed out that it is 200 on the site he corrected himself to the effect that 'the manufacturer told us that it was 180 and then they told us that in fact it is 200'. I totally believed Carl, but not the marketing dept of the chinese co who wrote this figure - hence my comment.

So you seem to have some special insight into exactly how and why this happened, please provide your sources as I have, and likely you would be right. But that does not mean you can pontificate the way you do - I did say it was pure speculation and this is a forum where speculations should be allowed. It kind of looks that when you exhausted out the argument on the flatness cancelling issue you started poining out my inferior knowledge - I never said I have extensive electric bike knowledge nor am I a posting grandmaster like yourself. In fact I have been reading your inputs and I mostly take them on board, but here is one I din't:

Certainly less power will be used cruising at 8 mph than at 15 mph, but the differences are very small on the flat in fact, and academic anyway, since no-one is normally going to cruise at 8 mph

I mean the power difference between 8 and 15mph on the flat is huge, not very small.

 

[flecc]

I mean the power difference between 8 and 15mph on the flat is huge, not very small.

I knew you meant that, but I disagree, it is not huge.

On the Salisbury motor question, I'm quoting from my knowledge of what is produced at the Chinese end and how and when it has been marketed, not from Powacycle themselves.

I didn't exhaust any arguments, and have no objection to just speculation. But you seem to be determined to be confrontational and make wild statements and false technical comment, guessing your way through. It's not fair to speculate about reputable companies like eZee the way you've done in your inferences about motor ratings. It's not right to say "we have no way of knowing" in that matter when we do in fact know, that lack of knowledge being yours. It's not right to say we've said that notional is the same as nonsense, especially after it's been explained to you in detail what notional means and the fact that it's a legal definition, showing how it's not relevant to the technical matters we're concerned with.

Your responses to my attempts to help in your first thread were frankly arrogant and bordering on rudeness, and you don't seem to have improved much in this one. Since you obviously think you don't need advice or help and are certain of your infallibility in all these matters, I'll leave you to those delusions. I've better things to do than put up with your ill mannered conduct.

All the best with your performance measuring project.
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[coops]

chazpope, I have replied to your question in the relevant thread and all further discussion on that topic should be done there.

Stuart.

 

[chazpope]

I knew you meant that, but I disagree, it is not huge.

FYI the actual difference is something like 200% - this is a huge difference. Call it another one of my delusions if you like but the power required to push the bike through the air is proportional to the cube of its speed - twice the speed requires 8 times more power - hence the big difference.

 

[flecc]

FYI eh, that arrogance shows again! That's the theory Chazpope, and I know it as well as you and knew it before you were born.

But I also have those little things called experience and practical knowledge, and therefore know of the common circumstance which frequently largely undoes that relationship.

You've also been shown how those additional factors change theory by Ian, when he illustrated how the Sprint and Torq upset your test theory, and by me, when I showed you how two other bikes, the Quando and Chopper actually inverted the theory.

But the difference in this posting is that I'm not going to tell you what it is that upsets your theory for two reasons. First because as I've indicated before I'm fed up with your denial responses based on bluff, and second, because if you are as knowledgeable as you purport to be, you don't need me to tell you.
.

 

[coops]

FYI the actual difference is something like 200% - this is a huge difference. Call it another one of my delusions if you like but the power required to push the bike through the air is proportional to the cube of its speed - twice the speed requires 8 times more power - hence the big difference.

For information purposes, 8 times more power is a 700% increase, not 200%. Your facts are correct, but your conclusions are relative and only applicable to cycling on the flat, which isn't what the rest of us are discussing here and its getting very confusing, so to avoid that please try to keep your posts in the same context as everyone else.

From 8mph to 15mph the power increase required is relatively big, maybe even 8 times as you say, but the power output for both, on the flat, is small compared to whats required to climb even a modest hill at a modest speed, say a 7% gradient at 9mph, which requires over 2.5 times the power of 15mph on the flat (thats over 7.5 times more than 8mph on the flat) for even a modest rider & bike weight of 100kg combined.

These facts are easily verifiable from experience: try cycling at 8mph and then 15mph, on a flattish surface, then try doing 8mph up a 7% gradient (if you can find one!), and make your own mind up which is the biggest difference.

Stuart.

 

[chazpope]

coops,

both figures 8 and 200 are correct and relevant. You will note above that I referred only to the air resistance component of the power as being 8 times bigger; you also have the rolling resistance power into play which is linearly proportional to speed so the combined effect is about 3 times more or 200%difference.

I am specifically referring to flecs quoted wildly inaccurate statement about cruising power difference on the flat and I am not making a big deal about it other than to point out that imho it is totally wrong. What you say re power uphill is true but does not prove or disprove this particular point.

 

[coops]

Ok chazpope, fair enough: I agree on your figures, clear now; I misunderstood your statement re 8 times and 200%.

I think you still don't see though: flecc's statement was accurate, especially in the context of the topic being spoken of i.e. hillclimbing - thats how I understood it. Your last statement is equally valid in the context of cycling on the flat. The problem as I see it is confusion over the topic of discussion, and the context of statements.

What I said about power needed for hills was to illustrate that.

Stuart.

 

[allotmenteer]

coops,

both figures 8 and 200 are correct and relevant. You will note above that I referred only to the air resistance component of the power as being 8 times bigger; you also have the rolling resistance power into play which is linearly proportional to speed so the combined effect is about 3 times more or 200%difference.

I am specifically referring to flecs quoted wildly inaccurate statement about cruising power difference on the flat and I am not making a big deal about it other than to point out that imho it is totally wrong. What you say re power uphill is true but does not prove or disprove this particular point.

Enough rope yet Flecc?

 

[flecc]

I'm still smiling Paul.

Chazpope isn't the first to confuse the status of theory which is very condition dependent with the status of immutable physical laws and accord the wrong importance.

Like most who make that same mistake, he appears to have a closed mind.

Stuart's observation meaning that 200% of next to nothing is still next to nothing is also relevant of course, and next to nothing isn't huge in any usage.

However, my point is solely on the relative values on the flat in the same conditions as Chazpope's statement.
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