As someone who has had their ass saved by 2400W of acceleration on my most powerful skateboard, when I in a panic hit full throttle to dodge out of the way of a car that was about to ram into my side as I was in a bike crossing moving at walking speed…
It has its moments.
Driver turned a corner and accelerated towards and past the red light that was supposed to keep me safe. Near-missed two pedestrians on either side, too, but I would have been smack dab in the middle of the bumper had I stayed where I was.
My problem is more with how these things are geared. Power isn’t top speed. Top speed is a function of the design voltage of the battery, the KV of the motor, and the gearing between it and the wheel. It doesn’t matter what the wattage you can push is. Gear the drive-train for a sane top speed, and any excess power is only a good thing. Simply enabling greater acceleration. There to be deployed for fun, or like in my case, safety. A higher energy drive-train also works better in the other direction, allowing for MUCH more powerful regen braking.
Still I agree, the casual rider has little use for too much more than 1000W. At that wattage you already get plenty of torque when geared for the 25-30 kph range that the casual user of an ebike or escooter is comfortable riding at.
There absolutely needs to be a cultural shift in how high-performance PEVs are considered. The ads and the early adopters treat it like an extreme sport which it is ok to engage in at way too close a proximity to onlookers.
Gear the drive-train for a sane top speed, and any excess power is only a good thing. Simply enabling greater acceleration.
For sure, I agree with this. However, that’s not how current PEVs are designed, so wattage seems to always linked to raw power and speed (this is a selling feature, no doubt), which isn’t what you want/need in an urban environment when most places have laws that restrict motors to under 500w and speeds to 25km/h or slower. LOL
Having witnessed e-scooters before the advent of hyper scooters, I was optimistic in their future. But it seems like “low-end” (i.e. legal) e-scooters are being pushed away for electric racing motorcycles without seats. And nobody wants those around pedestrians or on bike paths. E-bikes have already become a problem in too many cities, and we don’t need more backlash because of other overpowered PEVs.
Voltage determines motor RPMs, amperage determines torque. (Simplified)
50V at 60A is 3000 watts, but so is 25V at 120A.
But the system configured to run at 50V can achieve twice the speed of the one at 25V. The 25V system is also 3000W, but all it can do with that is achieve its top speed really fast.
It’s a bit more complex than that. At lower speed the higher cmvotage system can function like the lower voltage one, as at low RPM and therefore low motor voltage the ESC can pump up the amps while remaining within the power limit of the battery (up to the amperage limit of the motor), but once the ESC is pushing the voltage coming out of the battery right into the motor, there is no going faster even with watts to spare. Maintaining speed doesn’t take as much energy as accelerating, so as you hit top speed, power consumption actually goes down.
Unless you sacrifice the amps/torque/acceleration to gain voltage/top speed, more power doesn’t mean a faster PEV.
I imagine one would have a motor controller that included something along the lines of a variable frequency drive (VFD) and a boost converter for something in the 4.5KW range, which would largely mitigate the issue and open up the door to using a small forklift battery as the foundation of a motorcycle.
As someone who has had their ass saved by 2400W of acceleration on my most powerful skateboard, when I in a panic hit full throttle to dodge out of the way of a car that was about to ram into my side as I was in a bike crossing moving at walking speed…
It has its moments.
Driver turned a corner and accelerated towards and past the red light that was supposed to keep me safe. Near-missed two pedestrians on either side, too, but I would have been smack dab in the middle of the bumper had I stayed where I was.
My problem is more with how these things are geared. Power isn’t top speed. Top speed is a function of the design voltage of the battery, the KV of the motor, and the gearing between it and the wheel. It doesn’t matter what the wattage you can push is. Gear the drive-train for a sane top speed, and any excess power is only a good thing. Simply enabling greater acceleration. There to be deployed for fun, or like in my case, safety. A higher energy drive-train also works better in the other direction, allowing for MUCH more powerful regen braking.
Still I agree, the casual rider has little use for too much more than 1000W. At that wattage you already get plenty of torque when geared for the 25-30 kph range that the casual user of an ebike or escooter is comfortable riding at.
There absolutely needs to be a cultural shift in how high-performance PEVs are considered. The ads and the early adopters treat it like an extreme sport which it is ok to engage in at way too close a proximity to onlookers.
For sure, I agree with this. However, that’s not how current PEVs are designed, so wattage seems to always linked to raw power and speed (this is a selling feature, no doubt), which isn’t what you want/need in an urban environment when most places have laws that restrict motors to under 500w and speeds to 25km/h or slower. LOL
Having witnessed e-scooters before the advent of hyper scooters, I was optimistic in their future. But it seems like “low-end” (i.e. legal) e-scooters are being pushed away for electric racing motorcycles without seats. And nobody wants those around pedestrians or on bike paths. E-bikes have already become a problem in too many cities, and we don’t need more backlash because of other overpowered PEVs.
Wattage is amps times voltage.
Voltage determines motor RPMs, amperage determines torque. (Simplified)
50V at 60A is 3000 watts, but so is 25V at 120A.
But the system configured to run at 50V can achieve twice the speed of the one at 25V. The 25V system is also 3000W, but all it can do with that is achieve its top speed really fast.
It’s a bit more complex than that. At lower speed the higher cmvotage system can function like the lower voltage one, as at low RPM and therefore low motor voltage the ESC can pump up the amps while remaining within the power limit of the battery (up to the amperage limit of the motor), but once the ESC is pushing the voltage coming out of the battery right into the motor, there is no going faster even with watts to spare. Maintaining speed doesn’t take as much energy as accelerating, so as you hit top speed, power consumption actually goes down.
Unless you sacrifice the amps/torque/acceleration to gain voltage/top speed, more power doesn’t mean a faster PEV.
I imagine one would have a motor controller that included something along the lines of a variable frequency drive (VFD) and a boost converter for something in the 4.5KW range, which would largely mitigate the issue and open up the door to using a small forklift battery as the foundation of a motorcycle.
I’m not aware of any BLDC ESCs that implement boost conversion.
Looking it up it seems such a circuit would be beefy indeed when built to handle the amperages of propulsion.
Controlling the voltage coming out of the battery is already done using pulse width modulation, but this can only reduce the voltage, not increase it.
There’s little point in boosting the voltage to achieve higher top speed, as configuring a battery pack for voltage is very easy.
To the point that I’m here lamenting that PEV designs are upping the top speed even when utterly unnecessary.
I was joking, yout silly potato. The forklift battery thing was supposed to be a tipoff.
Why would there be anything wrong with a forklift battery?
A battery pack is a battery pack.
Drop an /s next time.
Forklift batteries are also ballast. They’re lead-acid and weight 600lbs at the minimum. It’s a comically bad idea to use one for a personal vehicle.
Thanks. I’ll go ahead and file that under “obvious common knowledge” going forward. /S
I know how lithium packs work and how to program a VESC. That’s all.