Range and Wh....
- Thread starter brucehawsker
- Start date
But my point was the people carriers would also have to be large - in order to carry the large people. I understood the point you were making, but your large people wouldn't fit in a small people carrier (That is a small people-carrier, not a small-people carrier). It is all relative to the norm I suppose, so maybe we should ask him.
What do you think, Norm?
Colin
What do you think, Norm?
Colin
Back on Topic
The Efficiency of an Electric Bike.
Well, the first thing is to keep rolling resistance on the flat to a minimum. This means highest quality bearings, AND no residual resitance in a hub mo0tor when no power is applied - not obvious but a significant factor in efficient motor design.
Secondly, when power is applied, a major impact on efficiency is what happens when that power is applied. Worn cogs in the motor, or a slow battery or motor response, add up to significant wastage of battery power.
Thirdly the power profile (Amps vs time vs speed) can be highly inefficient, effectively wasting Wh with no or marginal improvement in user expereince.
Fourthly, power may be applied without need during a ride. Reducing amps judiciously to encourage modest pedalling is good both for battery and human longevity.
Fiftly, a battery may be abused by high amp demands without warning, just to fulfil some theoreticians imagined 'need for speed'. A slower ramp is better for the battery and produces a longer range.
Sixthly, what the BMS does when a cell is failing to step up to the mark (as they all do randomnly) makes a huge impact on the range. Alloowing cells to rest, and detecting hotspots early, is critical to larger ranges for given Wh-age.
I could go on. There is no magic here. Just detail attention to the results of analysis of many real world trips to tweak the controller in a way which is optimal for a particular clien't needs, or even for a particular journey, or even in stages up a particular hill (so elegantly implemented for the skilled ebike rider on the new Stork Raader).
There is more I could add, and some of it is commercially sensitive. But it means our bikes can consistently meet the 7-8Wh/mile target, or 40+ miles, or 3+ hours at 12+mph.
Hope this helps - I have not invented Wh out of nowhere - just focussed on the engineering of how best to use a good battery and and a good motor. The magic lies in the software....
The Efficiency of an Electric Bike.
Well, the first thing is to keep rolling resistance on the flat to a minimum. This means highest quality bearings, AND no residual resitance in a hub mo0tor when no power is applied - not obvious but a significant factor in efficient motor design.
Secondly, when power is applied, a major impact on efficiency is what happens when that power is applied. Worn cogs in the motor, or a slow battery or motor response, add up to significant wastage of battery power.
Thirdly the power profile (Amps vs time vs speed) can be highly inefficient, effectively wasting Wh with no or marginal improvement in user expereince.
Fourthly, power may be applied without need during a ride. Reducing amps judiciously to encourage modest pedalling is good both for battery and human longevity.
Fiftly, a battery may be abused by high amp demands without warning, just to fulfil some theoreticians imagined 'need for speed'. A slower ramp is better for the battery and produces a longer range.
Sixthly, what the BMS does when a cell is failing to step up to the mark (as they all do randomnly) makes a huge impact on the range. Alloowing cells to rest, and detecting hotspots early, is critical to larger ranges for given Wh-age.
I could go on. There is no magic here. Just detail attention to the results of analysis of many real world trips to tweak the controller in a way which is optimal for a particular clien't needs, or even for a particular journey, or even in stages up a particular hill (so elegantly implemented for the skilled ebike rider on the new Stork Raader).
There is more I could add, and some of it is commercially sensitive. But it means our bikes can consistently meet the 7-8Wh/mile target, or 40+ miles, or 3+ hours at 12+mph.
Hope this helps - I have not invented Wh out of nowhere - just focussed on the engineering of how best to use a good battery and and a good motor. The magic lies in the software....
Interesting, thanks for posting this Bruce. However, I can get 8Wh out of my DIY Bafang Peugeot bike using a low cost Xeicheng 116 based controller and the low speed assist setting, how does that work then? No fancy power profiles, 13mph average speed rides over some very hilly terrain. The controller is programable for peak and sustained current draw limits but there's no profiling as such. Also what is a slow battery?
The answer is here:
I am sure if you applied this magic software you may get an extra 0.001Wh or even an extra 100metres
That's how - and we all know what "magic" really is.
Colin
D
Deleted member 4366
Guest
Regarding efficiency of an electric bike - or any bike for that matter, I would say that the type of tyres have a substantial effect. I can't justify it wwith figures, but I would say that my pedalling effort has been reduced and my range increased, both by maybe as much as 25% since I changed from MTB tyres to Scwalbe City Slicks.
Tyres will always make the biggest difference in energy required, also the bike being well maintained and having the exact gearing and crank length for your personal requirements.
Then you have to consider the riding position which will determine how efficiently you use your leg muscles.
Then streamlining and weight of bike, and finally the magic software ingredient.
Colin
Then you have to consider the riding position which will determine how efficiently you use your leg muscles.
Then streamlining and weight of bike, and finally the magic software ingredient.
Colin
Streamlining is tricky. Even on recumbents. It's a shame bents come in so many different sizes (and are so expensive) so it's hard to find add on streamlining.
As for the rest of it, its amazing just how badly setup and maintained most people's bikes are. Pumping the tyres, freeing up all the bearings and oiling the chain can make a huge difference.
Tyre pressure is something I forgot to mention as an individual item. Good point
Streamlining - if you add extra streamlining aids you also increase the weight which counteracts it to an extent. What I meant was related to riding position: certainly not using the "sit up and beg" position, and general clutter on the bike.
I have a large tall mirror, GPS on a mount, three lots of lights on the front and panniers and top-box on the back. If I got rid of that lot my Wisper would possibly go all day and night on one charge; it would certainly go a bit faster and further, and be a bit easier to get on and off trains.
Colin
Streamlining - if you add extra streamlining aids you also increase the weight which counteracts it to an extent. What I meant was related to riding position: certainly not using the "sit up and beg" position, and general clutter on the bike.
I have a large tall mirror, GPS on a mount, three lots of lights on the front and panniers and top-box on the back. If I got rid of that lot my Wisper would possibly go all day and night on one charge; it would certainly go a bit faster and further, and be a bit easier to get on and off trains.
Colin
On streamlining, have any of you come across a velomobile? Its essentially a recumbent but with a streamlined hull which you climb into.
Popular in Holland, unassisted speeds even up to 30mph (!), protection from the elements and costing about the same as a top-end electric bike.
The basic idea is combining the efficiency of a cycle machine with the aerodynamic profile of a car - and win. May not take off in the UK compared with a very flat Holland...
Interesting: http://en.wikipedia.org/wiki/Velomobile
Popular in Holland, unassisted speeds even up to 30mph (!), protection from the elements and costing about the same as a top-end electric bike.
The basic idea is combining the efficiency of a cycle machine with the aerodynamic profile of a car - and win. May not take off in the UK compared with a very flat Holland...
Interesting: http://en.wikipedia.org/wiki/Velomobile
Most people lovingly remember the C5? That was an electric velomobile.
With the lighter unpowered ones you have problems controlling them in gusty crosswinds, and the only advantage is they can keep you dry in the rain. I tried racing one in the 60's in Holland but as I had never ridden a recumbent before I didn't do very well - and that is putting it very kindly.
Colin
With the lighter unpowered ones you have problems controlling them in gusty crosswinds, and the only advantage is they can keep you dry in the rain. I tried racing one in the 60's in Holland but as I had never ridden a recumbent before I didn't do very well - and that is putting it very kindly.
Colin
Just 4 big armchairs, with either 16" wheels and a 250W, or with hydraulic legs.... like the walking table.... et violaBut that's why I stressed large-people carriers at the end Colin, carriers of large people, not many people!
Maybe long wheelbase Transits fitted with four large armchairs would fit the bill.
.
YouTube - Gassi gehen mit Couchtisch
Thats really the main reason velomobile and recumbent bikes haven't taken off in the UK, it looks kind of silly pushing one up a hill.... great in the square mile but no real practical application apart from the Broads...
Would it be that fashionable?
What I wouldn't get though is being so low in such busy traffic.
Velomobiles are neat, as are tadpole trikes. And they're prime candidates for electrifying. But what I really want is a streamlined recumbent bicycle.
Not quite sure why though!
Not quite sure why though!
Is there an award for 'most off topic'?
Quantum Mechanics? Simples! Is Schrödinger's cat dead or alive? You have to open the box to collapse the wave function, until you do..........oh hold on, there goes the doorbell............
Last edited:
This is dead easy to understand. It's what one refers to when wanting to maintain the impression of having knowledge when no other answer is actually available.
AKA the scientist's cop-out.
.
and if you left your I PLOD plugged in on the table wouldn't it get stolen?Would it be that fashionable?
What I wouldn't get though is being so low in such busy traffic.
Related Articles
-
MTF Enterprises announces acquisition of EMU Electric Bikes- Started by: Pedelecs
-
Wisper 806T folding bike wins Which? ‘Best Buy’- Started by: Pedelecs
-
Sustrans calls for protected cycle lanes- Started by: Pedelecs
-
Amazon launch their first UK e-cargo micromobility hub- Started by: Pedelecs
