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about electric motors
- Thread starter jucasan
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DuctTapedGoat
Active Member
I don't know jack about electrics, I'll put that out right now.
Common sense will tell me that the difference is this.
Regenerative Braking - Battery charges when you brake.
Regenerative Motors - Battery charges when you ride.
The noticeable differences are these.
Regenerative Braking Motor - You will have a faster speed, more torque, but your battery won't last as long as a full on Regenerative Motor.
Regenerative Motor - You won't have as much speed or torque, but your battery will last longer as some of all the power exterted will go back into the battery.
Now, keeping in mind I don't know jack about electrics, that's all opinion based on reasoning.
Please, someone correct me if I'm wrong.
Common sense will tell me that the difference is this.
Regenerative Braking - Battery charges when you brake.
Regenerative Motors - Battery charges when you ride.
The noticeable differences are these.
Regenerative Braking Motor - You will have a faster speed, more torque, but your battery won't last as long as a full on Regenerative Motor.
Regenerative Motor - You won't have as much speed or torque, but your battery will last longer as some of all the power exterted will go back into the battery.
Now, keeping in mind I don't know jack about electrics, that's all opinion based on reasoning.
Please, someone correct me if I'm wrong.
retromike3
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a question about power
The main reason I decided to forgo the electric mode is that it is impossible to get the the same power out of even the best electric system than you can out of a gasoline engine. my little half a gallon gas tank will get me over fifty miles at about forty miles an hour.(I don't have a speedometer so I don't really know how fast I am going officer) and even at three dollars a gallon it is still much less expensive than the bus.
electric is much more quiet and smooth and better for the environment but unless it can get me there quickly and when I want to it will remain a unfulfilled dream.
Mike Frye
The main reason I decided to forgo the electric mode is that it is impossible to get the the same power out of even the best electric system than you can out of a gasoline engine. my little half a gallon gas tank will get me over fifty miles at about forty miles an hour.(I don't have a speedometer so I don't really know how fast I am going officer) and even at three dollars a gallon it is still much less expensive than the bus.
electric is much more quiet and smooth and better for the environment but unless it can get me there quickly and when I want to it will remain a unfulfilled dream.
Mike Frye
Ypedal
Member
In general, electrics are good for 20 miles or less.. if you have to go much longer than this you get into special setups and more expense.. certainly possible but not always economical... i've build a 100 km range ebike.... but i never go that far so it was a waste with excess weight i did not need..
Regen.... bottom line is that ebikes are not heavy enough to make it worth while, you can only generate so much energy from a system and it's a factor of how steep the hill is and how much weight you are trying to slow down...
It's "generally" accepted that you are better off coasting/freewheeling down hills than trying to recouperate that energy..
There is possibility of using the motor ( only direct drive hub motors need apply, as geared setups freewheel and canot force the motor to spin and generate energy) as an E-brake, turning the motor into an anti-lock braking system to save on brake pads but again, unless you have to go down a reallllly big hill at a reduced speed, it's not worth it.
Cars, EV, on the other hand, have alot more weight, and can generate more energy in the process .. but ebikes benefit from simplicity and less weight.
Also, be aware that regen can in some situations damage your battery pack, if you head down a big hill from a full charge, you risk over-charging your pack and frying it.. complex electronics can prevent this, but again it's not an off the shelf options at this point in time.
Regen.... bottom line is that ebikes are not heavy enough to make it worth while, you can only generate so much energy from a system and it's a factor of how steep the hill is and how much weight you are trying to slow down...
It's "generally" accepted that you are better off coasting/freewheeling down hills than trying to recouperate that energy..
There is possibility of using the motor ( only direct drive hub motors need apply, as geared setups freewheel and canot force the motor to spin and generate energy) as an E-brake, turning the motor into an anti-lock braking system to save on brake pads but again, unless you have to go down a reallllly big hill at a reduced speed, it's not worth it.
Cars, EV, on the other hand, have alot more weight, and can generate more energy in the process .. but ebikes benefit from simplicity and less weight.
Also, be aware that regen can in some situations damage your battery pack, if you head down a big hill from a full charge, you risk over-charging your pack and frying it.. complex electronics can prevent this, but again it's not an off the shelf options at this point in time.
still confuse
Is this true? Probably a regenerative motor is more atractive than a regenerative brake to me
Is this true? Probably a regenerative motor is more atractive than a regenerative brake to me
Ypedal
Member
There seems to be some confusions regarding terminology here.....
All electric motors can create energy by being forced to turn, mechanically, or can be fed energy from a battery to make it turn..
example, the alternator in your car is an electric motor, the gas motor is forcing it to spin at X rpm creating a certain voltage that recharges your 12v lead acid battery in the process...
In the same way, a direct drive hub motor, powered by a battery and controller, has a max rpm depending on the voltage of the battery.
More voltage = higher rpm
So lets say that a bike with a hub motor on 36v goes 20mph on the flats at full throttle... you keep the throttle on full and roll down a big hill where the bike goes over 20mph, by going down the hill faster than the max rpm of the motor at 36 battery volts, the motor generates higher voltage because it's forced to spin faster by the hill and your momentum, at a certain point you will be producing energy from the motor that can be fed back into the battery and increase the battery voltage and put energy back into the pack...
That exists right now with most hub systems... right out of the box.
However...
With the right electronics, you can rig a switch that disconects the battery from the controller, and makes use of the energy produced by the motor while on the downhill right down to 0 rpm and you can do one of 2 things with this energy, either run it thru a big resistor to turn it into heat ( Resistive Braking ) or feed it into electronics that can step up the voltage and feed the battery pack ( Regenerative Braking )
confused yet ?
All that said, unless you roll up and down severe mountains, most places on earth will not produce any meaningfull enery from all this, it can be usefull to bring you to a stop saving on brake pads, but regen to charge your battery pack typically only delivers a few small percent points back of usable power because you have to factor in the losses in those electronics on top of the added weight and complexity of the system....... just not worth it right now until someone makes a plug and play solution for it and i don't know of any readily available right now.
I have had the opertunity to ride Justin L's ( ebikes.ca ) ebike that he crossed canada with, something like 6000 kms for 8$ of electricity ( he left vancouver BC, and i'm in Moncton NB, so coast to coast ) .. he made his own controller, it has means of using the throttle as a variable adjust braking system, you pull a brake lever attached to a wire ( not a brake cable, but an electric wire ) that turns the throttle into a brake lever by causing resistance in the motor according to how much you twist.... really cool and very smooth !!!
All electric motors can create energy by being forced to turn, mechanically, or can be fed energy from a battery to make it turn..
example, the alternator in your car is an electric motor, the gas motor is forcing it to spin at X rpm creating a certain voltage that recharges your 12v lead acid battery in the process...
In the same way, a direct drive hub motor, powered by a battery and controller, has a max rpm depending on the voltage of the battery.
More voltage = higher rpm
So lets say that a bike with a hub motor on 36v goes 20mph on the flats at full throttle... you keep the throttle on full and roll down a big hill where the bike goes over 20mph, by going down the hill faster than the max rpm of the motor at 36 battery volts, the motor generates higher voltage because it's forced to spin faster by the hill and your momentum, at a certain point you will be producing energy from the motor that can be fed back into the battery and increase the battery voltage and put energy back into the pack...
That exists right now with most hub systems... right out of the box.
However...
With the right electronics, you can rig a switch that disconects the battery from the controller, and makes use of the energy produced by the motor while on the downhill right down to 0 rpm and you can do one of 2 things with this energy, either run it thru a big resistor to turn it into heat ( Resistive Braking ) or feed it into electronics that can step up the voltage and feed the battery pack ( Regenerative Braking )
confused yet ?
All that said, unless you roll up and down severe mountains, most places on earth will not produce any meaningfull enery from all this, it can be usefull to bring you to a stop saving on brake pads, but regen to charge your battery pack typically only delivers a few small percent points back of usable power because you have to factor in the losses in those electronics on top of the added weight and complexity of the system....... just not worth it right now until someone makes a plug and play solution for it and i don't know of any readily available right now.
I have had the opertunity to ride Justin L's ( ebikes.ca ) ebike that he crossed canada with, something like 6000 kms for 8$ of electricity ( he left vancouver BC, and i'm in Moncton NB, so coast to coast ) .. he made his own controller, it has means of using the throttle as a variable adjust braking system, you pull a brake lever attached to a wire ( not a brake cable, but an electric wire ) that turns the throttle into a brake lever by causing resistance in the motor according to how much you twist.... really cool and very smooth !!!
Last edited:
DuctTapedGoat
Active Member
Not confusing at all - resistive braking makes a lot more sense, and I really dig that about the variable brake on the throttle!
There seems to be some confusions regarding terminology here.....
All electric motors can create energy by being forced to turn, mechanically, or can be fed energy from a battery to make it turn..
example, the alternator in your car is an electric motor, the gas motor is forcing it to spin at X rpm creating a certain voltage that recharges your 12v lead acid battery in the process...
In the same way, a direct drive hub motor, powered by a battery and controller, has a max rpm depending on the voltage of the battery.
More voltage = higher rpm
So lets say that a bike with a hub motor on 36v goes 20mph on the flats at full throttle... you keep the throttle on full and roll down a big hill where the bike goes over 20mph, by going down the hill faster than the max rpm of the motor at 36 battery volts, the motor generates higher voltage because it's forced to spin faster by the hill and your momentum, at a certain point you will be producing energy from the motor that can be fed back into the battery and increase the battery voltage and put energy back into the pack...
That exists right now with most hub systems... right out of the box.
However...
With the right electronics, you can rig a switch that disconects the battery from the controller, and makes use of the energy produced by the motor while on the downhill right down to 0 rpm and you can do one of 2 things with this energy, either run it thru a big resistor to turn it into heat ( Resistive Braking ) or feed it into electronics that can step up the voltage and feed the battery pack ( Regenerative Braking )
confused yet ?
All that said, unless you roll up and down severe mountains, most places on earth will not produce any meaningfull enery from all this, it can be usefull to bring you to a stop saving on brake pads, but regen to charge your battery pack typically only delivers a few small percent points back of usable power because you have to factor in the losses in those electronics on top of the added weight and complexity of the system....... just not worth it right now until someone makes a plug and play solution for it and i don't know of any readily available right now.
I have had the opertunity to ride Justin L's ( ebikes.ca ) ebike that he crossed canada with, something like 6000 kms for 8$ of electricity ( he left vancouver BC, and i'm in Moncton NB, so coast to coast ) .. he made his own controller, it has means of using the throttle as a variable adjust braking system, you pull a brake lever attached to a wire ( not a brake cable, but an electric wire ) that turns the throttle into a brake lever by causing resistance in the motor according to how much you twist.... really cool and very smooth !!!
Thanks Ypedal, now I'm starting to understand a bit more about this. Now, what is the function of the controller?
Ypedal
Member
An ebike Controller is the Electrical equivalent of a Carburetor .
It allows you to use a throttle to regulate the power going to the motor.
A Brushed motor does not really need a controller, it can technically just have an ON/OFF switch, there are only 2 wires that exit the motor, + and -
A Brushless motor has no brushes, and wired in such a way that there are 3 power wires that exit. ie: 3 phase. The controller needs to time 2 of the 3 wires at a time in a certain pattern to push or pull a magnetic field inside the motor.. Most motors also have 5 more tiny gauge wires going to three hall sensors inside. These tell the controller if the copper coils have a North or a South magnet facing them, this is essential for a powerfull Instant Start brushless setup. Some motors and controllers only use the 3 power wires and disregard the hall sensors ( Sensorless ), some requrie that you pedal first to get the magnets spinning, other controllers can use software to bump the motor and take off from there, sensorless is not ideal at a dead stop and sometimes fails to start if the motor is heavily loaded.
Everyone has played with magnets, North and North push eachother, N and South attact... well the magnets in a Brushless motor are in a ring of N-S-N-S-N-S so if you time a positive or negative flow of electricityy thru a copper coil, it will either push or pull against the magnet facing it.. causing it to spin.
The throttle does not vary the voltage to the motor, the motor always sees the same voltage, but to make the motor turn slower at partial throttle, the controller turns the power on and off very quickly ( Pulse Width Modulation, often PWM seen on controller pages ) ..
Most controllers have a " Max Amp " rating, regardless of the voltage you plug into it, so if you run a 20 amp controller at 36v you get peak 20x(batt operating voltage that varies depending on battery type ) but on a fresh charge 20a x 40v = 800w peak
Take the same controller and put 48v to it and you get 20a x 55v = 1100w peak
Once you reach cruising speed, the controller usually does not have to limit the amps anymore, it just lets the motor draw as many watts as it needs to keep the speed constant, at 20mph that is usually 200 to 300w .. at 30mph that goes up because of wind resistance so 500 to 700w ... notice almost double the power for 10 more mph !!
ugh.. ES is offline with upgrades going on.. i'm loosing my mind ... information junkie the internet turns you into lol..
It allows you to use a throttle to regulate the power going to the motor.
A Brushed motor does not really need a controller, it can technically just have an ON/OFF switch, there are only 2 wires that exit the motor, + and -
A Brushless motor has no brushes, and wired in such a way that there are 3 power wires that exit. ie: 3 phase. The controller needs to time 2 of the 3 wires at a time in a certain pattern to push or pull a magnetic field inside the motor.. Most motors also have 5 more tiny gauge wires going to three hall sensors inside. These tell the controller if the copper coils have a North or a South magnet facing them, this is essential for a powerfull Instant Start brushless setup. Some motors and controllers only use the 3 power wires and disregard the hall sensors ( Sensorless ), some requrie that you pedal first to get the magnets spinning, other controllers can use software to bump the motor and take off from there, sensorless is not ideal at a dead stop and sometimes fails to start if the motor is heavily loaded.
Everyone has played with magnets, North and North push eachother, N and South attact... well the magnets in a Brushless motor are in a ring of N-S-N-S-N-S so if you time a positive or negative flow of electricityy thru a copper coil, it will either push or pull against the magnet facing it.. causing it to spin.
The throttle does not vary the voltage to the motor, the motor always sees the same voltage, but to make the motor turn slower at partial throttle, the controller turns the power on and off very quickly ( Pulse Width Modulation, often PWM seen on controller pages ) ..
Most controllers have a " Max Amp " rating, regardless of the voltage you plug into it, so if you run a 20 amp controller at 36v you get peak 20x(batt operating voltage that varies depending on battery type ) but on a fresh charge 20a x 40v = 800w peak
Take the same controller and put 48v to it and you get 20a x 55v = 1100w peak
Once you reach cruising speed, the controller usually does not have to limit the amps anymore, it just lets the motor draw as many watts as it needs to keep the speed constant, at 20mph that is usually 200 to 300w .. at 30mph that goes up because of wind resistance so 500 to 700w ... notice almost double the power for 10 more mph !!
ugh.. ES is offline with upgrades going on.. i'm loosing my mind ... information junkie the internet turns you into lol..
Last edited:
wheelbender6
Well-Known Member
Locomotives use the Resistive Braking to save brake wear. While going downhill, the current from the motor is fed to resisters and escapes as heat, just as Ypedal described.
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