DJI enter Ebike market

[Dogtrousers]

What I'm trying to say, possibly badly, is that these e-bikes do not necessarily give the riders the hill climbing or acceleration performance of super-fit or super-human riders. For whatever reason I'm not sure, but the headline figure of say 500W motor output, does not remotely translate into what a pro cyclist with an 500w FTP could do. It's not a fair comparison.

This could be the source of my failure to understand why 500W could be needed.

I'll remain a bit sceptical. Especially considering my chagrin at my supposedly less fit friends climbing up the Grand Colombier on their 250W bikes when I had been planning and training for it for over a year.

But it doesn't really matter much to me. I avoid shared paths most of the time - and it's here that I foresee problems. And to me, on the road, ebikes are just another vehicle.

 

[bonzobanana]

Most ebikes have 250W ratings stickers sold in Europe but actual wattage is not really related to that. It can be anything from about 140W continuous to about 900W continuous and still be sold as 250W. Real wattage is the voltage multiplied by the continuous maximum rating of the controller. So if you have a mid-drive motor which is 36V and has a 23A controller (continuous) then it will be a maximum of 42V (freshly charged 36V battery) x 23A which is up to 966W of course the average voltage of the battery pack as it discharges is 36V and 23A is only allowed for climbing hills when the torque sensor sees that the rider is applying the most power. A true 250W motor would only be allowed 5A at 48V or 7A at 36V. So we already have ebikes effectively 1000W but they are sold as 250W. In the US many ebikes sold as 500W and 750W are sold as 250W in Europe and there may even be examples of 1000W ebikes sold as 250W over here although I'm currently not aware of any.

The EU ebike legislation makes little sense and seems to be written in a way that is confusing and manipulative perhaps to reduce imports from China but in the last year or so China are also selling high wattage ebikes as 250W in Europe. I would say most of these are 750W so still not as powerful as most European designed mid-drive motor ebikes that are sold as 250W. However this DJI ebike motor like some Bafang models seems to compete head on with European designed mid-drive motors in wattage power.

It's getting more and more ridiculous to pretend any of these ebikes have 250W motors. Certification should be honest and based on engineering standards not be a political tool.

 

[Dogtrousers]

OK @bonzobanana I'm out of this discussion! I didn't really understand any of that

There was me foolishly thinking that a 250W bike would put out ... I dunno ... 250W??

 

[bonzobanana]

OK @bonzobanana I'm out of this discussion! I didn't really understand any of that

There was me foolishly thinking that a 250W bike would put out ... I dunno ... 250W??

I don't think you were foolish for thinking that with regards most certification that would be a safe assumption but when it comes to ebikes it just goes out the window pretty much.

 

[CXRAndy]

I've ridden powerful Ebikes 1500W. Up a steep hill 10% plus, to hold 10 mph it requires over 1000W plus me having to put in some effort , not gasping but breathing firmly.

I've ridden the same hill on a race bike when I was much fitter at 4mph gasping to breath. I'm 90kg plus

If you want to get people out riding in realistic comfy pace and in physical comfort then 250W isn't going to cut it for hillier parts of the country.

Those commuting will want to wear a suit for office and arrive sweat free. You need to have more power, more speed.

 

[CXRAndy]

OK @bonzobanana I'm out of this discussion! I didn't really understand any of that

There was me foolishly thinking that a 250W bike would put out ... I dunno ... 250W??

It's not 250W at the wheel of the bike. It's the motor rating. By the time drive train losses are factored in it will be much lower.

 

[Dadam]

It's not 250W at the wheel of the bike. It's the motor rating. By the time drive train losses are factored in it will be much lower.

Yes, also it's the electrical power input of the motor (volts and amps), it's not even the mechanical output at the motor spindle. No motor is 100% efficient. A quick google suggests 85%-90% for brushless motors which is quite good but some watts are lost there, then more watts are lost in the motor gearbox, and yet more in the drivetrain.
Whereas measuring cyclists' FTP, they're measuring the output through power meters (although I assume this is to the crank not the wheel).

 

[Dogtrousers]

Yes, also it's the electrical power input of the motor (volts and amps), it's not even the mechanical output at the motor spindle. No motor is 100% efficient. A quick google suggests 85%-90% for brushless motors which is quite good but some watts are lost there, then more watts are lost in the motor gearbox, and yet more in the drivetrain.
Whereas measuring cyclists' FTP, they're measuring the output through power meters (although I assume this is to the crank not the wheel).

Yes, so drive train losses included. Unless, of course you have a hub power meter, but they aren't so common.

 

[classic33]

It's not solely about having 500/1000/1500 Watts. It's about limiting speed and burdensome legislation.

250W is pathetic for anything but flat.

You have 250W FTP I have around the same , but that is me going at threshold HR which is making me sweat a hell of a lot.

An unfit rider mayput out as little as 100W and that will be trying quite hard


To comfortably climb a steep hill not be blowing a gasket for the rider 500W minimum is required to help an unfit rider. To give 500W for a several minute climb, requires a motor of at least 750W to cope with overheating for extended periods of max output.

I think the speed limit should lifted to 20 mph, allowing say 500-~1500W as standard, not place excessive licencing upon owners. Riders could and would use their bikes for local trips, commuting.

Look at Europe, where Ebikes are even more popular. They have standard Ebike and speed Ebikes. The legislation for 28mph isn't burdensome, small licence plate and nominal fees to use on the road.

People have options in Europe, the UK doesn't, folk/gig economy riders set themselves up for what they need to get the job done.

Cycling is supposed to be exercise. You normally sweat when you exert yourself.
If you want a bike that does the work for you, I'd suggest going down the licensed route in time for next April.
Ireland has already implemented similar rules to mainland Europe. Only they have charged from the outset for those bikes that fail to meet the basic requirements of the standardized EU rules.
In some cases they've even removed bikes, and e-scooters, from their roads that failed to meet the very simple regulations. And their answer to those who thought the law didn't apply to them.

 

[CXRAndy]

Cycling is supposed to be exercise. You normally sweat when you exert yourself.

Cycling means all sorts for different people. I get my V02 max from racing on Zwift. I get my enjoyment from tootling around on my e-bike. Wife and I rode 60 miles on Sunday over varied terrain, e-bikes flattened the hills and quelled the headwinds, keeping us in Z1/2 for effort. Still plenty of good exercise for over 4 hours of riding.

 

[ebikeerwidnes]

It's not solely about having 500/1000/1500 Watts. It's about limiting speed and burdensome legislation.

250W is pathetic for anything but flat.

You have 250W FTP I have around the same , but that is me going at threshold HR which is making me sweat a hell of a lot.

An unfit rider mayput out as little as 100W and that will be trying quite hard


To comfortably climb a steep hill not be blowing a gasket for the rider 500W minimum is required to help an unfit rider. To give 500W for a several minute climb, requires a motor of at least 750W to cope with overheating for extended periods of max output.

I think the speed limit should lifted to 20 mph, allowing say 500-~1500W as standard, not place excessive licencing upon owners. Riders could and would use their bikes for local trips, commuting.

Look at Europe, where Ebikes are even more popular. They have standard Ebike and speed Ebikes. The legislation for 28mph isn't burdensome, small licence plate and nominal fees to use on the road.

People have options in Europe, the UK doesn't, folk/gig economy riders set themselves up for what they need to get the job done.

I don't agree
There are few steep long hills around here but I used to live in North Wales

There was a long steep hill that was on a nice country road that avoided the main roads
I could JUST about get up it on my old 180W Powacycle that was limited to the pre-2016 regs
I could get up it far more easily on my modern 250W ebike

The difference between 250W and 1000w is that the 1000W enables you to get up that hill without little effort
rather than getting up with with less effort than it would take on a normal bike
in other words - the 1000W is a moped - and should be treated as such


The privileges given to legal bikes is to allow people to ride them as if they were unpowered and as they don;t have that much of an advantge
extending the regulation to include more powerful ebikes means including machines that have far greater capabilities for an average person riding it than they would have with a normal bike

IMO

 

[CXRAndy]

Yes I want to climb hills with Z1/2 effort. I go to restaurants, friends and shopping.. I don't want to arrive sweaty at all

 

[classic33]

Yes I want to climb hills with Z1/2 effort. I go to restaurants, friends and shopping.. I don't want to arrive sweaty at all

Slow down and take longer then.
If time taken, and not arriving "sweaty" are your main concerns chose a different form of transport.

 

[ebikeerwidnes]

Yes I want to climb hills with Z1/2 effort. I go to restaurants, friends and shopping.. I don't want to arrive sweaty at all

So you want a motorised for of transport where the motor does all the work
That is called a motorbike or car

 

[CXRAndy]

It doesn't do all the work or my HR would be at resting bpm. I ride in Z1/Z2, that is optimal 'training' for endurance. I can stay in that zone whatever the terrain, attain a comfortable pace. I believe our 60 mile ride the other day took a little over 4 hours travelling time, so that is less than 15mph.

There you go excellent endurance zone