People ask me this all the time about my ebike "so does it charge while you pedal". These people also get a
To be fair that's a legitimate question, I can't see a reason why it wouldn't be possible to have a system which does so?
Electric cars
- Thread starter LabR@t
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To be fair that's a legitimate question, I can't see a reason why it wouldn't be possible to have a system which does so?
They all (fully electric cars, not hybrids) have an ancillary battery, a small one but it’s there.
When the car is off the HV battery is physically disconnected from the drivetrain. The 12V battery activates the contractors for the HV when you turn the car on and runs the cars other systems like lights etc.
Think about it…
Because using the motor as a generator adds a large amount of resistance meaning you have to pedal harder to travel the same distance. It’s the same reason why ebikes don’t have regen.
an ebike can put out 250w of power, most casual riders can’t sustain 250w for any length of time. Now imagine peddling with minus 250w to the power your legs are putting out, you wouldn’t be able to move the bike more than a few meters before collapsing in a sweaty heap.
Ebikes use a different type of motor which free wheels with minimal resistance when you don’t use it because that’s exactly what you want in an ebike. Bikes are all about having as little friction as possible so you can go further with less effort.
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Deleted member 66701
Deleted member 66701
Soldato
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It is possible and has been done.
Deleted member 236143
Deleted member 236143
I am sure ages ago there was some mad wind tunnel experiment that the transfer of power from a cyclist via leg muscle was thee greatest power ratio ever making the bicycle thee most sufficient energy to power or performance ratio ever.
But I will take the electric scooter please. Thanks.
But I will take the electric scooter please. Thanks.
article here about ebike regen, been said already really
what i wonder is why more electric cars or any, dont have solar panels on the roof bonnet ect im not saying they would tootle away under sun power but say parked up at work for 8 hours wouldn't it be a useful trickle top up, if we ignore cost would the surface area give a useful output?
edit, ive googled
what i wonder is why more electric cars or any, dont have solar panels on the roof bonnet ect im not saying they would tootle away under sun power but say parked up at work for 8 hours wouldn't it be a useful trickle top up, if we ignore cost would the surface area give a useful output?
edit, ive googled
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People ask me this all the time about my ebike "so does it charge while you pedal". These people also get a
Yeah it tells me that people are leaving school unware of the basic fundamentals of science and reality itself. oh well.
To be fair, I still don't think it's as silly a question as the self charging car. On an eBike you have got two sources of power, the battery/motor aren't even needed all the time. To me the logic of it would be you get help going up an ascent, but then skim power back off coming down a hill. I don't think anyone would expect it to last forever, but if you can get some back when descending, that seems logically sound?
I would have thought this is the bigger road block, which I don't think you would expect everyone to necessarily know?
Soldato
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I assumed the question was a case of why can't bikes have regen braking. I'd assume weight would be the problem, as with the response of the motor being different, maybe its to do with the motor. A good comparison would be a hybrid, they do have some element of self charge, even if it's just a trickle charge.
Moon man patiantly reposts link
https://evelo.com/blogs/learn/why-don-t-more-bikes-use-regenerative-braking
https://evelo.com/blogs/learn/why-don-t-more-bikes-use-regenerative-braking
As per the link, you’d get about as much power back to power the radio and lights for a few minutes per day in ideal conditions.
To put it in perspective, the slowest Tesla has a single motor which can output 211kw of power and will use about 10kwh of electricity to drive 40 miles if driven carefully. 200w of solar could get you back less than 1kwh in a day in perfect conditions, in reality you’ll generate less than half that (perhaps even less than a third) on a car for lots of very good reasons (e.g. the panels are flat where as they actually need to be pitched towards the sun to get peek performance).
It’s not the motor or the weight that are dealbreakers. Like I said, think about when you ride a bike, the last thing you want is additional resistance. High end bike manufacturers literally to everything they can to get resistance out of the system, be that aerodynamic or drivetrain. It’s the only real difference between a mid range bike and a super high end one.
Taking any meaningful amount of power your legs are putting out and putting it into a battery will slow you down and that is the last thing you want on a bike. The idea of an ebike is that it assists you and doesn’t make it harder.
There is also the fundamental issue of power conversion and there is no such thing as a free lunch. Going from mechanical (legs) to electrical (via motor) to chemical (battery) and back again will probably have 20-30% losses if not more. So you’ll not get anything like what you put in back.
The key difference with a hybrid is that the power comes from liquid fuel and you have much more flexibility in how you attach the motor to the drivetrain. As said above, there is no such thing as a free lunch (or a “self charging” hybrid), it’s a marketing term. All of the power comes from the liquid fuel you put in at £1.30/litre. The hybrid system captures some of the energy which would normally be wasted (via friction brakes) using a motor/generator and stores it in a battery. Fundamentally, that energy still came from the liquid fuel.
Since you seem interested in actually explaining rather than just being a condescending **** like @amigafan2003, is there a reason you couldn't have a continue pedalling to charge the battery when you'd otherwise be freewheeling down hill? It's pretty obvious you wouldn't want to be losing pedal energy when you're actually trying to move the bike
You'd need a switch to engage/disengage the charging mechanism so it was only active when required, and all of which would have course add weight, but I can think of several places I've ridden regularly where I've been freewheeling down hill for a km or 2, and while having a rest is always nice, having a bit more charge to help go up the next hill would be too
Reading the link above suggests its not worth it because of the minimal amount of energy regained, but that is talking about regen breaking with a different type of motor (also not worth it != impossible).
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Because you’d still be losing energy in the conversion and you would have added resistance ALL the time.
Say you were peddling at 100w during that time, you’ll only get 60-70w back from the motor when you want it. To me that makes no sense and I might as well just pedal the 60-70w when I need it as it’s less effort.
It’s pretty rare when you are freewheeling on a bike that you actually want to slow down (via regen, you’d have to be peddling against regen braking to generate the energy and maintain speed). More often than not you get to the bottom of the decent and you have to start peddling again before you pick up too much speed it becomes dangerous.
Say you were peddling at 100w during that time, you’ll only get 60-70w back from the motor when you want it. To me that makes no sense and I might as well just pedal the 60-70w when I need it as it’s less effort.
It’s pretty rare when you are freewheeling on a bike that you actually want to slow down (via regen, you’d have to be peddling against regen braking to generate the energy and maintain speed). More often than not you get to the bottom of the decent and you have to start peddling again before you pick up too much speed it becomes dangerous.
Deleted member 66701
Deleted member 66701
That's different than charging while you are pedalling though - you're describing regenerative braking which ebikes with direct drive motors can do. You only recover around 5% of energy though (due the already described losses/
inefficiency) but they aren't that common in Europe. Most of our motors are geared, which freewheel when unpowered so they are easier to pedal but cannot do regen.
they do, but only on direct drive motors, which have specific disadvantages over geared motors when used for ebikes (weight, resistance while pedalling) and the energy recovery is minimal anyway.
Since you seem interested in actually explaining rather than just being a condescending **** like @amigafan2003, is there a reason you couldn't have a continue pedalling to charge the battery when you'd otherwise be freewheeling down hill? It's pretty obvious you wouldn't want to be losing pedal energy when you're actually trying to move the bike
See above.
Exactly this, but to add a chain and sprockets is pretty efficient, about 97%. So if you are pedalling at 100w, it makes more sense to put the energy though the drive train at 97w than 70w into the battery and back out again.
FYI, I've been building and riding ebikes since 2008, so I know my ****.
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The fundamental reason why ebikes are built that way is because they are pedal assist bikes and not motorbikes.
If ebikes were built as motorbikes/mopeds (some are but they are illegal in Europe because they don’t meet the actual moped or motorbike requirements) then it makes sense they regen and they to have regen. Even scooters have regen but they are technically at motor vehicle at the moment and need to meet the relevant requirements, hence they are illegal outside of the ‘test’ schemes. You can get proper electric mopeds and motorbikes, they just have to meet the same regs as a combustion one.
But when the concept is for the motor to assist a person pedalling then having the ability to regen causes problems because the motor is permanently engaged and adds adds resistance all the time and you have to pedal against it. Fundamentally if the battery is flat or disconnected, the bikes just works like a normal bike. Throttles are illegal in ebikes in the U.K. and Europe unless you have an old one that was around before the regs changed.
If ebikes were built as motorbikes/mopeds (some are but they are illegal in Europe because they don’t meet the actual moped or motorbike requirements) then it makes sense they regen and they to have regen. Even scooters have regen but they are technically at motor vehicle at the moment and need to meet the relevant requirements, hence they are illegal outside of the ‘test’ schemes. You can get proper electric mopeds and motorbikes, they just have to meet the same regs as a combustion one.
But when the concept is for the motor to assist a person pedalling then having the ability to regen causes problems because the motor is permanently engaged and adds adds resistance all the time and you have to pedal against it. Fundamentally if the battery is flat or disconnected, the bikes just works like a normal bike. Throttles are illegal in ebikes in the U.K. and Europe unless you have an old one that was around before the regs changed.
Generally you are better off not increasing resistance to charge the battery because the energy gain is not worth it compared to the energy expenditure of the rider.Since you seem interested in actually explaining rather than just being a condescending **** like @amigafan2003, is there a reason you couldn't have a continue pedalling to charge the battery when you'd otherwise be freewheeling down hill? It's pretty obvious you wouldn't want to be losing pedal energy when you're actually trying to move the bike
You'd need a switch to engage/disengage the charging mechanism so it was only active when required, and all of which would have course add weight, but I can think of several places I've ridden regularly where I've been freewheeling down hill for a km or 2, and while having a rest is always nice, having a bit more charge to help go up the next hill would be too
Reading the link above suggests its not worth it because of the minimal amount of energy regained, but that is talking about regen breaking with a different type of motor (also not worth it != impossible).
However I can see certain situations were it may be beneficial assuming the maths works out.
On a flat or downhill road you may want to skim some energy from the rider especially if they are exceeding the motors cutoff speed. Then use it on the uphill since that is were the motor assistance is really useful. Whether you can harvest enough energy for it to be useful is another question.
No, I meant from my pedalling. If it skims 50W off me while I'm pedalling downhill (or possibly even on flats) that would be fine.
Tried this when I was a student. Didn't work.