Paint it any colour you like, 8 hp will only do about 55 MPH.Mr. Dazzle wrote: ↑Sun Jan 10, 2021 1:23 pm You do have to consider horsepower ratings on electric vehciles slightly differently. Unlike a piston engine an EV can produce peak power across most of the rev range...it essentially operates in 2 regions "torque limited" when the motor can put out peak torque, or "power limited" (at higher speeds) when it can output peak power. EVs essentially always have either full power or full torque available, depending how fast you're going.
Piston engines on the other hand only produce peak power at a narrow speed range.
In simple terms EVs are always in the power band.
It means an 8bhp electric vehicle has a lot more "go" than an 8bhp conventional vehcile. Imagine having an engine that was on cam at full power all the time...electric motors are a lot like that.
Electric bikes, the next step
- Yorick
- Posts: 16670
- Joined: Sat Mar 14, 2020 8:20 pm
- Location: Paradise
- Has thanked: 10212 times
- Been thanked: 6860 times
Re: Electric bikes, the next step
-
- Posts: 13870
- Joined: Mon Mar 16, 2020 7:57 pm
- Location: Milton Keynes
- Has thanked: 2545 times
- Been thanked: 6206 times
Re: Electric bikes, the next step
Its more a comment on the nature of electric drive than anything.
Even if you were to say an electric bike is effectively twice as powerful as a petrol one - which it ain't - this particular electric bike would still only be as grunty as a tuned 125.
Even if you were to say an electric bike is effectively twice as powerful as a petrol one - which it ain't - this particular electric bike would still only be as grunty as a tuned 125.
- Horse
- Posts: 11482
- Joined: Sun Mar 15, 2020 11:30 am
- Location: Always sunny southern England
- Has thanked: 6129 times
- Been thanked: 5044 times
Re: Electric bikes, the next step
And I'll say this again: my best ever - literally laughing out loud - biking moment was flat out downhill, overtaking a 911, on a Honda CG125.
If it's designed and sold as an urban commuter, anything more is a bonus.
Even bland can be a type of character
-
- Posts: 13870
- Joined: Mon Mar 16, 2020 7:57 pm
- Location: Milton Keynes
- Has thanked: 2545 times
- Been thanked: 6206 times
Re: Electric bikes, the next step
I used to overtake people all the time in my 1 litre Nissan Micra with the engine turned off. There was a big hill on the way to work, if I started at the top at 70mph and switched off the engine (said Micra had no power brakes and no power steering) I would frequently overtake people in the fast lane
Someone did quite accurately point out it didn't really matter if it was a 1 litre Micra or a 3 litre BMW when the engine was turned off.
Someone did quite accurately point out it didn't really matter if it was a 1 litre Micra or a 3 litre BMW when the engine was turned off.
- weeksy
- Site Admin
- Posts: 23311
- Joined: Sat Mar 14, 2020 12:08 pm
- Has thanked: 5437 times
- Been thanked: 13028 times
Re: Electric bikes, the next step
But as a city commuter bike that's all it needs to do. If you live 2-3 miles from town or even a couple of back lanes from town, it's perfect. Plenty of people commute from one side of London to the outskirts on the other side without ever seeing more than 55.Yorick wrote: ↑Sun Jan 10, 2021 2:22 pmPaint it any colour you like, 8 hp will only do about 55 MPH.Mr. Dazzle wrote: ↑Sun Jan 10, 2021 1:23 pm You do have to consider horsepower ratings on electric vehciles slightly differently. Unlike a piston engine an EV can produce peak power across most of the rev range...it essentially operates in 2 regions "torque limited" when the motor can put out peak torque, or "power limited" (at higher speeds) when it can output peak power. EVs essentially always have either full power or full torque available, depending how fast you're going.
Piston engines on the other hand only produce peak power at a narrow speed range.
In simple terms EVs are always in the power band.
It means an 8bhp electric vehicle has a lot more "go" than an 8bhp conventional vehcile. Imagine having an engine that was on cam at full power all the time...electric motors are a lot like that.
- weeksy
- Site Admin
- Posts: 23311
- Joined: Sat Mar 14, 2020 12:08 pm
- Has thanked: 5437 times
- Been thanked: 13028 times
Re: Electric bikes, the next step
https://www.motorcyclenews.com/news/ele ... atteries/9
Swappable batteries on the horizon: Giants team up to make swap-in, swap-out battery packs a reality
Honda, KTM, Piaggio and Yamaha have signed an agreement to create a ‘swappable batteries consortium’ with a view to standardising batteries in electric bikes. Battery standardisation has been one of the key stumbling blocks to electrification, but it looks like this will finally be overcome.
Swappable batteries on the horizon: Giants team up to make swap-in, swap-out battery packs a reality
Honda, KTM, Piaggio and Yamaha have signed an agreement to create a ‘swappable batteries consortium’ with a view to standardising batteries in electric bikes. Battery standardisation has been one of the key stumbling blocks to electrification, but it looks like this will finally be overcome.
-
- Posts: 804
- Joined: Mon Mar 16, 2020 4:04 pm
- Location: S. Wales
- Has thanked: 299 times
- Been thanked: 559 times
Re: Electric bikes, the next step
Potentially a great idea and size permitting could transfer to cars. Instead of stopping for fuel, stop at the ‘fuel’ station, swap batteries and off you go again.weeksy wrote: ↑Tue Mar 02, 2021 4:42 pm https://www.motorcyclenews.com/news/ele ... atteries/9
Swappable batteries on the horizon: Giants team up to make swap-in, swap-out battery packs a reality
Honda, KTM, Piaggio and Yamaha have signed an agreement to create a ‘swappable batteries consortium’ with a view to standardising batteries in electric bikes. Battery standardisation has been one of the key stumbling blocks to electrification, but it looks like this will finally be overcome.
- Horse
- Posts: 11482
- Joined: Sun Mar 15, 2020 11:30 am
- Location: Always sunny southern England
- Has thanked: 6129 times
- Been thanked: 5044 times
Re: Electric bikes, the next step
Worth noting that the agreement also included reference to some other electric vehicle applications too.
Even bland can be a type of character
-
- Posts: 13870
- Joined: Mon Mar 16, 2020 7:57 pm
- Location: Milton Keynes
- Has thanked: 2545 times
- Been thanked: 6206 times
Re: Electric bikes, the next step
As we've discussed before, either up there ^^^ or elsewhere on the forum, it seems like swappable batteries are being targeted at small bikes (scooters basically). This makes sense, because with current volume automotive battery tech the packs are just too damned big for high power bikes.
Take a look at this guy swapping a battery (pic is from the MCN article). And then consider than in ~100bhp bikes the battery is more like 50, 60 or even 100kg!
Unfortunately battery power, battery capacity and battery size are linked. You're unlikely to see a high power battery that is also small and light capacity...not for a while anyway. But you will one day not too far off.
EDIT: Just for scale, Lithium Ion batteries are currently about 500-1200W/kg power density. I.e. for every 1kg of battery you can get about 500-1200W of power out. It's a really wide spread because with EV stuff you can massively overate it for "a bit" before it overheats and catches fire. So a 50kW battery might actually be able to output more than 100kW for a few seconds.
If you have a 100kW electric motor (about 135bhp) you need a slightly more than 100kW battery to power it due to efficiency losses. So say for argument's sake that is a 105kW battery. Said batter is going to be somewhere in the range between 80kg and 200kg. You're not swapping that in a hurry! THe only real reason electric bikes are "a bit lardy" rather than "catastrophically heavy" is 'cause the engine - the electric motor - is hugely lighter than the piston engine it replaced.
Take a look at this guy swapping a battery (pic is from the MCN article). And then consider than in ~100bhp bikes the battery is more like 50, 60 or even 100kg!
Unfortunately battery power, battery capacity and battery size are linked. You're unlikely to see a high power battery that is also small and light capacity...not for a while anyway. But you will one day not too far off.
EDIT: Just for scale, Lithium Ion batteries are currently about 500-1200W/kg power density. I.e. for every 1kg of battery you can get about 500-1200W of power out. It's a really wide spread because with EV stuff you can massively overate it for "a bit" before it overheats and catches fire. So a 50kW battery might actually be able to output more than 100kW for a few seconds.
If you have a 100kW electric motor (about 135bhp) you need a slightly more than 100kW battery to power it due to efficiency losses. So say for argument's sake that is a 105kW battery. Said batter is going to be somewhere in the range between 80kg and 200kg. You're not swapping that in a hurry! THe only real reason electric bikes are "a bit lardy" rather than "catastrophically heavy" is 'cause the engine - the electric motor - is hugely lighter than the piston engine it replaced.
-
- Posts: 91
- Joined: Thu May 21, 2020 9:04 pm
- Has thanked: 23 times
- Been thanked: 19 times
Re: Electric bikes, the next step
Given that a lot of riders a powering phones/comms/satnav/cameras/clothing etc through bikes have any manufacturers made any allowances for this?
-
- Posts: 804
- Joined: Mon Mar 16, 2020 4:04 pm
- Location: S. Wales
- Has thanked: 299 times
- Been thanked: 559 times
Re: Electric bikes, the next step
The way it’s going, the bikes will be charged by the phones next!dayglo jim wrote: ↑Mon Mar 08, 2021 11:38 am Given that a lot of riders a powering phones/comms/satnav/cameras/clothing etc through bikes have any manufacturers made any allowances for this?
-
- Posts: 719
- Joined: Wed Apr 22, 2020 11:30 am
- Has thanked: 164 times
- Been thanked: 308 times
Re: Electric bikes, the next step
Say that a bike does 10miles / kwh in city riding at an average 20 miles per hour and it is charging a phone via USB at 2amps...dayglo jim wrote: ↑Mon Mar 08, 2021 11:38 am Given that a lot of riders a powering phones/comms/satnav/cameras/clothing etc through bikes have any manufacturers made any allowances for this?
For each mile the bike uses 100Wh of battery and the phone charger uses 0.5Wh.
So the range will be reduced by a whole nine yards [sic] for each mile travelled in charging the phone.
-
- Posts: 13870
- Joined: Mon Mar 16, 2020 7:57 pm
- Location: Milton Keynes
- Has thanked: 2545 times
- Been thanked: 6206 times
Re: Electric bikes, the next step
I work for an EV motor/controller company...perhaps unsurprisingly the company founder drives an electric car.dayglo jim wrote: ↑Mon Mar 08, 2021 11:38 am Given that a lot of riders a powering phones/comms/satnav/cameras/clothing etc through bikes have any manufacturers made any allowances for this?
I once pointed out to him that he'd left his headlights on in the carpark. His reply was that he'd done the maths and he figured out it would be something like 2 weeks before the lights discharged the battery hence he CBA to go turn them off.
- Cousin Jack
- Posts: 4422
- Joined: Mon Mar 16, 2020 4:36 pm
- Location: Down in the Duchy
- Has thanked: 2533 times
- Been thanked: 2268 times
Re: Electric bikes, the next step
Let's hope he doesn't feel the cold. LED lights may be pretty insignificant on batteries, heaters are not. A 20w light may be pretty bright, a 20w heater is not going to make much of an impact. Of course he is unlikely to leave the heater on in the car park.Mr. Dazzle wrote: ↑Mon Mar 08, 2021 12:02 pm I work for an EV motor/controller company...perhaps unsurprisingly the company founder drives an electric car.
I once pointed out to him that he'd left his headlights on in the carpark. His reply was that he'd done the maths and he figured out it would be something like 2 weeks before the lights discharged the battery hence he CBA to go turn them off.
Cornish Tart #1
Remember An Gof!
Remember An Gof!
-
- Posts: 13870
- Joined: Mon Mar 16, 2020 7:57 pm
- Location: Milton Keynes
- Has thanked: 2545 times
- Been thanked: 6206 times
Re: Electric bikes, the next step
Most EVs primarily use waste heat from the battery/motors/controller to heat the cabin, much like an ICE car. Even though they're massively more efficient than ICE engines they still have a couple of hundred watts of waste heat.
-
- Posts: 136
- Joined: Thu Mar 19, 2020 9:05 pm
- Has thanked: 95 times
- Been thanked: 107 times
Re: Electric bikes, the next step
Yep. Swappable batteries are only useful for small commuter bikes.Mr. Dazzle wrote: ↑Tue Mar 02, 2021 7:33 pm If you have a 100kW electric motor (about 135bhp) you need a slightly more than 100kW battery to power it due to efficiency losses. So say for argument's sake that is a 105kW battery. Said batter is going to be somewhere in the range between 80kg and 200kg. You're not swapping that in a hurry! .
Also consider that the next generation ev bikes will have a formed battery shape (rather than a big box) and be a structural member.
-
- Posts: 91
- Joined: Thu May 21, 2020 9:04 pm
- Has thanked: 23 times
- Been thanked: 19 times
Re: Electric bikes, the next step
Sorry guys, should have thought that one through. Still in the mindset of an ICE with a puny battery struggling with cameras, comms, AHO and the fan going crazy in the summer, had to bumpstart the capo a few times when there wasn't enough juice to crank it over.dayglo jim wrote: ↑Mon Mar 08, 2021 11:38 am Given that a lot of riders a powering phones/comms/satnav/cameras/clothing etc through bikes have any manufacturers made any allowances for this?
-
- Posts: 3020
- Joined: Mon Mar 16, 2020 9:30 pm
- Location: Less that 50 miles away from Moscow, but which one?
- Has thanked: 1339 times
- Been thanked: 1709 times
Re: Electric bikes, the next step
On about how things are charged, some of the newest EV's have vehicle to grid charging which on just one car isn't that much use but on hundreds of thousands provides worthwhile grid level storage capabilitity.
-
- Posts: 4428
- Joined: Mon Mar 16, 2020 9:02 pm
- Has thanked: 830 times
- Been thanked: 1235 times
Re: Electric bikes, the next step
I'm not spending thousands of pounds on a battery with a decent range just to find when I need it that the leccy company has half drained it because the sun went in. They need to find a different mass storage solution.
-
- Posts: 3020
- Joined: Mon Mar 16, 2020 9:30 pm
- Location: Less that 50 miles away from Moscow, but which one?
- Has thanked: 1339 times
- Been thanked: 1709 times
Re: Electric bikes, the next step
The point being you get to choose to allow this and even get paid for it. Vehicles spend a huge amount of time just taking up space and not providing any worthwhile gains.
But you knew that didn't you.