Perhaps the only answer is to theoretically check for maximum range in identical circumstances, but the industry will reasonably want those to be based on best conditions. Like the car tests and just as useless!

perhaps the answer is to quote only the battery capacity. That way, customers can see clearly that a 36V 5AH battery is half as good as a 36V 10AH battery. As for range, give a simple indication that if you pedal more, you extend the range and if you only rotate the cranks, then it's 10WH per mile on flat roads without headwind. That way, a 36V 5.2AH battery gives at most 190WH or 19 miles with very little pedaling.

perhaps the answer is to quote only the battery capacity. That way, customers can see clearly that a 36V 5AH battery is half as good as a 36V 10AH battery. As for range, give a simple indication that if you pedal more, you extend the range and if you only rotate the cranks, then it's 10WH per mile on flat roads without headwind. That way, a 36V 5.2AH battery gives at most 190WH or 19 miles with very little pedaling.

 

But how many people understand what battery capacity is or how to measure it? Not many...

 

In our experience even people that think they understand it still call it a "ten amp battery" not a "ten amp hour battery"

 

Thus there is no getting away from the fact that to market to the general public you have to quote range in miles because people understand that.

 

No single company is ever going to shoot themselves in the foot by going to market with an understated range when other companies with equivalent products are quoting more ambitious ranges.

 

The SWYTCH claim of "50 miles" is perfectly reasonable, understandable, and far more fair than what other companies are claiming in similar circumstances.

 

The only way to change things is to have an international standard / testing procedure that can be followed so everyone is on the same page.

But how many people understand what battery capacity is or how to measure it? Not many...

are you sure not many would understand battery capacity?

after all, the capacity is on the label.

As for range, give a simple indication that if you pedal more, you extend the range and if you only rotate the cranks, then it's 10WH per mile on flat roads without headwind. That way, a 36V 5.2AH battery gives at most 190WH or 19 miles with very little pedaling.

 

That still wouldn't do though. The worst case and the most popular quality ebikes of 2006/7, the powerful but legal Ezee Torq and Quando models, consistently ate 24 Wh per mile when not putting in any pedal effort, even with my light circa 63 kilos and avoiding hills. Both models, 15 miles from 360 Wh across a number of forum members when we surveyed them. For one guy it was almost 33 Wh per mile!

 

And it wouldn't suit the torque controlled crank motor bikes which issue power according to rider input. Some will scarcely move without appreciable rider input.

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But how many people understand what battery capacity is or how to measure it? Not many...

 

In our experience even people that think they understand it still call it a "ten amp battery" not a "ten amp hour battery"

 

Thus there is no getting away from the fact that to market to the general public you have to quote range in miles because people understand that.

 

No single company is ever going to shoot themselves in the foot by going to market with an understated range when other companies with equivalent products are quoting more ambitious ranges.

 

The SWYTCH claim of "50 miles" is perfectly reasonable, understandable, and far more fair than what other companies are claiming in similar circumstances.

 

The only way to change things is to have an international standard / testing procedure that can be followed so everyone is on the same page.

 

There you go: "..... an international standard / testing procedure that can be followed so everyone is on the same page." - Eureka!

If you do some market research you'll find that a very small fraction of the mass market (i.e. people that aren't already into eBikes) have any idea whatsoever what an Ah or a Wh is, let alone what Amps or Volts are exactly. Most find it very confusing especially the difference between an Ah capacity at 24V and Ah at 36V.

 

We take it for granted that it's common knowledge among the eBike community what an Ah or a Wh is and what it measures, and how that translates into what kind of range you can expect. But someone who hasn't studied physics or worked in electronics can't be expected to learn all of this just so that they can be eligible to purchase an eBike.

 

This is particularly important because the eBike market has been niche for a while, but that is changing, and it is becoming a mass-market.

 

The Car industry (the best established mass-market to reference i think) adopted MPG because people understand Miles, and Gallons, and because they are common metrics. It's only natural that the eBike industry also adopts something simple and based on miles, so that people can understand it.

 

Of course, it's not very precise quoting a range in miles, because of all the factors that can affect it, but at least it's understandable to everyone. And there is a certain standard forming on its own which is just the generally accepted conversion of Ah to miles - at the moment it seems to be very commonplace to convert 4-5Ah into "25 miles" and 10Ah or more into "50 miles". We are following this common practice and I think it's the right thing to do because it's actually not misleading, it's just not precise, and more importantly, customers understand it.

There you go: "..... an international standard / testing procedure that can be followed so everyone is on the same page." - Eureka!

 

Would you like to form a company to implement and regulate this? We would be your first customer, and if you're successful I think you could make ALOT of money in the long term

That still wouldn't do though. The worst case and the most popular quality ebikes of 2006/7, the powerful but legal Ezee Torq and Quando models, consistently ate 24 Wh per mile when not putting in any pedal effort, even with my light circa 63 kilos and avoiding hills. Both models, 15 miles from 360 Wh across a number of forum members when we surveyed them. For one guy it was almost 33 Wh per mile!

that is only because your bike is derestricted. If the assistance is cut off at 15mph, flat road, no headwind, little pedaling or rotating cranks only, you get very close to a known condition where everyone can relate to and the weight of the rider and his/her clothing don't matter much. The 10WH per mile is a typical value for such condition. If you ride on a torque system, then you can deduce the power consumption by the assist ratio, 300% (sport mode): 7.5WH/mile, 100% (eco mode): 5WH/mile.

that is only because your bike is derestricted.

 

That didn't apply to the Quando though, it's hub motor was geared in the 20" wheel to just about reach 16 mph when the battery was freshly charged, but average 15 mph overall.

 

It would happily trundle along on the flat at 15 mph continuously without pedalling, but always eating 24 Wh per mile. 15 Wh per mile was the best possible, simply because the single speed pedal gearing didn't allow exceeding it by pedalling. There's quite a few folders on the market like that, even some with gears.

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The Car industry (the best established mass-market to reference i think) adopted MPG because people understand Miles, and Gallons, and because they are common metrics.

that metric works because there is no user input. On a torque system, user input can be 50% in eco mode, 25% in sport mode. On a simple crank rotation system, user input could be anything from 0% to 100%.

As I said before, if you use 10WH/mile with little pedaling for your estimate on a system like the Swytch, then few people would question its validity.

For people who wonder how I came to 7.5WH for sport mode and 5WH for eco mode when you ride a torque pedelec, the formula is 10WH * n/(n+1), with n the assist ratio.

Would you like to form a company to implement and regulate this? We would be your first customer, and if you're successful I think you could make ALOT of money in the long term

I'm too old to be an entrepreneur - and too busy cycling.

I am keen to see what Wh/km I can obtain from the GSM when mounted to the trike, it is certainly more efficient than my upright! Anything under 7.5 Wh/km is fine. If I keep the cutoff to street legal 25 km/h the motor should only ever be used on climbing steeper hills so 5 Wh/km should be no problem. But I won't so it will be interesting to see how I get on.

the formula is 10WH * n/(n+1), with n the assist ratio.

 

There we are, problem solved. Quote the following in pedelec specifications:

 

Range: 10WH * n/(n+1), with n the assist ratio.

 

Customers should easily understand that.

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I have a feeling that this "how far it can go" issue really needs to be placed before a wider audience. Maybe it needs its own thread? (Hmmmm....on second thoughts......maybe not - it might get bigger than the Brexit one!)

I have a feeling that this "how far it can go" issue really needs to be placed before a wider audience. Maybe it needs its own thread? (Hmmmm....on second thoughts......maybe not - it might get bigger than the Brexit one!)

 

There's been threads in this forum on this question a number of times in the past eleven years. None has ever got near to resolving the issue, it's an impossible question to answer when one of the power supply elements, (human) is so grossly variable and the pedelec motor systems vary so widely.

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There's been threads in this forum on this question a number of times in the past eleven years. None has ever got near to resolving the issue, it's an impossible question to answer when one of the power supply elements, (human) is so grossly variable and the pedelec motor systems vary so widely.

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So it seems - but as has already been suggested, it just needs some sort of "standard test rig" (with no human involved) to come up with some sort of meaningful (though, admittedly, not universal) measurement that can be used for comparison. Presumably something that an academic institution could put together and be jointly funded/supported by all the reputable manufacturers and importers - with a test fee agreed. (Still, maybe we would just end up with the VW/Skoda scenario!)

This is all rather unessicary really. IMO the capacity of the battery in Wh should be enough information to compare with other bikes. The public don't have to know what a watt-hour is, but they will all know that 600 Wh is twice as much as 300 Wh.

 

Claiming "we've lied the same as everyone else" does not help the situation. If you have to give a number, an honest estimate of range, along with information about how a rider can increase this range (and possibly an explanation about why the competition's range figures are BS) is surely the best you can achieve and won't end up insulting a potential buyer's intelligence either.

it just needs some sort of "standard test rig" (with no human involved) to come up with some sort of meaningful (though, admittedly, not universal) measurement that can be used for comparison.

 

Very difficult to create a test rig for both torque controlled crank drive and rotation controlled hub motor bikes though. They are so different in the way they work.

 

And having different levels of switched power complicates matters, we've had pedelecs with as many as nine switched power levels while others have as little as three. Which do we choose on each to give fair comparisons? Maximum on each would be fair, but manufacturers would be deeply unhappy at the very short ranges that would result in.

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This is all rather unessicary really. IMO the capacity of the battery in Wh should be enough information to compare with other bikes. The public don't have to know what a watt-hour is, but they will all know that 600 Wh is twice as much as 300 Wh.

 

Claiming "we've lied the same as everyone else" does not help the situation. If you have to give a number, an honest estimate of range, along with information about how a rider can increase this range (and possibly an explanation about why the competition's range figures are BS) is surely the best you can achieve and won't end up insulting a potential buyer's intelligence either.

I do agree (sort of) - but for many people, especially those new to electric bikes, they do need a REALISTIC idea of how far a bike will take them on one charge. While each individual's proposed journey will have different ups and downs, some sort of "X miles - on a Y in Z incline" (based on an appropriate test under laboratory-type situation) would be hugely useful.

While each individual's proposed journey will have different ups and downs, some sort of "X miles - on a Y in Z incline" (based on an appropriate test under laboratory-type situation) would be hugely useful.

 

For me there's not very much difference between very hilly and less so, but that's because I let a bike have it's head on the downhills, using the stored kinetic energy so recovering some of what was expended uphill. For those too timid to do so who slow on the downhills, the stored energy is wasted in braking.

 

Sorry to keep observing these difficulties, but once again it highlights how the big differences between riders can affect range so greatly.

 

I do have a crude rule of thumb though, 12 Wh per mile being the average and most common across this forum over time for all riders and bikes in all riding circumstances. But the extremes ranging from the 5Wh of masochists to the 24Wh of lazy gits can mess that up.

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There we are, problem solved. Quote the following in pedelec specifications:

 

Range: 10WH * n/(n+1), with n the assist ratio.

 

Customers should easily understand that.

.

Great! That's exactly the kind of crystal clear communication we need to reach the mass market and get eBikes out there!

It's very simple to get a direct comparison. There's loads of variables that affect how far you can go with any ebike kit, but most of them relate to you, your rides and your bike that you fit the kit to. The other variables are probably insignificant compared with those, so if you want to compare the range that you'll get with different kits, you only have to look at the battery size (Wh). The distance you can go will be in direct proportion to the battery capacity, so you can go twice as far with a 14Ah 36v battery as you can with a 7Ah one. Simples!

 

The facts and calculations are simple and logical. It's the question"How far can I go on it" that's stupid, when wearing a coat can make 10% difference, though you could provide the logical answer, "probably somewhere between 5 miles and 100 miles". That's the same answer to "how long is a piece of string?" given in the MENSA book, except that it's something like between 1cm and 1km.

It's very simple to get a direct comparison. There's loads of variables that affect how far you can go with any ebike kit, but most of them relate to you, your rides and your bike that you fit the kit to. The other variables are probably insignificant compared with those, so if you want to compare the range that you'll get with different kits, you only have to look at the battery size (Wh). The distance you can go will be in direct proportion to the battery capacity, so you can go twice as far with a 14Ah 36v battery as you can with a 7Ah one. Simples!

 

The facts and calculations are simple and logical. It's the question"How far can I go on it" that's stupid, when wearing a coat can make 10% difference, though you could provide the logical answer, "probably somewhere between 5 miles and 100 miles". That's the same answer to "how long is a piece of string?" given in the MENSA book, except that it's something like between 1cm and 1km.

Agreed - but retailers/manufacturers insist on making distance/mileage claims and while they continue to do so, it seems to me that these claims need to be based on some standard "test". Rightly or wrongly, prospective purchasers (especially "newbies") really do want to get an idea of distance - even if it only allows them to conclude that "combination Z will take me x% further then combination Y, when traveling under the standard test conditions"

I have a feeling that this "how far it can go" issue really needs to be placed before a wider audience.

http://www.bike-eu.com/laws-regulations/nieuws/2017/10/leva-eu-survey-on-electric-range-test-for-e-bikes-in-type-approval-10131588

..Just out of curiousity, how does the power get from the box to the wheel? I see only 2 cables, 1x brake and 1x gears?

Edited October 10, 20178 yr by MikelBikel

Agreed - but retailers/manufacturers insist on making distance/mileage claims and while they continue to do so, it seems to me that these claims need to be based on some standard "test". Rightly or wrongly, prospective purchasers (especially "newbies") really do want to get an idea of distance - even if it only allows them to conclude that "combination Z will take me x% further then combination Y, when traveling under the standard test conditions"

It's absolutely impossible, and even if they did come up with a standard test, the results would be meaningless because the test parameters would be different from any real users ones. As I said, you can draw a comparison between the battery capacities, which is definitive, so no need for any fancy tests. The best estimate you can do is 3 miles per amp-hour, but when I can get 129 miles out of my battery on one charge one day and 20 miles the next day, you can see the futility of that.