4 ms·

> 10% is nothing to sneeze at but it also does not mean it is a game changer. They give a quote on a practical application: > The resulting Segway enjoyed a 5

> 10% is nothing to sneeze at but it also does not mean it is a game changer. They give a quote on a practical application: > The resulting Segway enjoyed a 50-percent increase in range, and four times the torque, which boosted the vehicle’s top speed and allowed it to climb a steep 20-percent grade. If that scales up linearly to electric cars, that's quite a boost.

jacquesm 7y ago
That's a pretty big if. A Segway is very much not a car. The relative weight of motor + batteries is a much higher proportion of the total mass of vehicle+occupant than it is in a vehicle. So it may be a boon to lightweight electric vehicles where that is true, but the same will not hold in proportion if the vehicle were much more massive and the weight of the batteries were much more massive. And Segways are speed limited, as are most other vehicles, top speed is rarely even an issue for anything on wheels, we can go up to speeds where you have to use aerodynamics not to end up flying.
- mikepurvis 7y ago
  50% range increase would be a huge boon to a vehicle like a Boosted Board. My V2 throws off a lot of heat and gets nowhere near the advertised 11km range.
  - jacquesm 7y ago
    > My V2 throws off a lot of heat and gets nowhere near the advertised 11km range. Heat losses come in many forms: - resistive losses in wiring - resistive losses in the batteries themselves (their Ri is nowhere near zero) - switching losses in the powertrain - slip losses between the field and the rotor If a piece of gear does not get its 'advertised performance' that can mean a defective product, deceptive advertising or plainly bad design, or a combination of all of these. Having a very expensive motor isn't suddenly going to solve any of that, you'll get an advertised range of 15 km while being able to do only 10 and you'll still feel cheated.
    - mikepurvis 7y ago
      It probably would go 11km on a straight and level run with no stopping for traffic lights or anything else. It's just that that's not realistic in an urban commute setting. I don't feel cheated, I'm just saying that even a modest bump in efficiency could make a big difference to this kind of vehicle, especially if affected both the propulsion and regen side of things.
esotericn 7y ago
The motors in a Model S make up about 5% of the car by weight.
coryrc 7y ago
That's a lie. Or, at least, there's another existing normal motor that can achieve at least nearly the same results. Existing motors are already 90+% efficient; it's not possible to make a 50% increase in range.
- mywittyname 7y ago
  I agree that they are at least misrepresenting their achievement. However, for the sake of argument, electric motor efficiency goes down quite a lot as overall power potential and RPM both drop. So it's possible they've come up with a sizeable efficiency improvement in a worst-case scenario, i.e., improving efficiency of a small motor in low RPM, part throttle situations. If that's the case, however, it doesn't really bode well for them, as their efficiency gains will not translate to the high-RPM, high-power motors used in cars. I'm not EE, but I do know that most engineering involves making trade-offs. So I wouldn't be surprised to learn that techniques to improve low-power, low-RPM efficiency probably sacrifices high-power, high-RPM efficiency.
  - rickycook 7y ago
    they did call out scooters and drones, so id guess you’re right
- bigiain 7y ago
  Possibly. You can get motors running 90+% efficiency, but only in a more or less narrow power band. If they can improve the efficiency in the ends of that bell curve, even if it's not an overall efficiency increase across the entire power/torque/rpm/"throttle" range, they might realistically be getting a 50% increase in "real world" use... Especially if they can do that in a way that removes the need for a gearbox (to keep the motor in it's highly efficient range).

jacquesm 7y ago

That's a pretty big if. A Segway is very much not a car. The relative weight of motor + batteries is a much higher proportion of the total mass of vehicle+occupant than it is in a vehicle. So it may be a boon to lightweight electric vehicles where that is true, but the same will not hold in proportion if the vehicle were much more massive and the weight of the batteries were much more massive. And Segways are speed limited, as are most other vehicles, top speed is rarely even an issue for anything on wheels, we can go up to speeds where you have to use aerodynamics not to end up flying.

mikepurvis 7y ago
50% range increase would be a huge boon to a vehicle like a Boosted Board. My V2 throws off a lot of heat and gets nowhere near the advertised 11km range.
- jacquesm 7y ago
  > My V2 throws off a lot of heat and gets nowhere near the advertised 11km range. Heat losses come in many forms: - resistive losses in wiring - resistive losses in the batteries themselves (their Ri is nowhere near zero) - switching losses in the powertrain - slip losses between the field and the rotor If a piece of gear does not get its 'advertised performance' that can mean a defective product, deceptive advertising or plainly bad design, or a combination of all of these. Having a very expensive motor isn't suddenly going to solve any of that, you'll get an advertised range of 15 km while being able to do only 10 and you'll still feel cheated.
  - mikepurvis 7y ago
    It probably would go 11km on a straight and level run with no stopping for traffic lights or anything else. It's just that that's not realistic in an urban commute setting. I don't feel cheated, I'm just saying that even a modest bump in efficiency could make a big difference to this kind of vehicle, especially if affected both the propulsion and regen side of things.

esotericn 7y ago

The motors in a Model S make up about 5% of the car by weight.

coryrc 7y ago

That's a lie. Or, at least, there's another existing normal motor that can achieve at least nearly the same results. Existing motors are already 90+% efficient; it's not possible to make a 50% increase in range.

mywittyname 7y ago
I agree that they are at least misrepresenting their achievement. However, for the sake of argument, electric motor efficiency goes down quite a lot as overall power potential and RPM both drop. So it's possible they've come up with a sizeable efficiency improvement in a worst-case scenario, i.e., improving efficiency of a small motor in low RPM, part throttle situations. If that's the case, however, it doesn't really bode well for them, as their efficiency gains will not translate to the high-RPM, high-power motors used in cars. I'm not EE, but I do know that most engineering involves making trade-offs. So I wouldn't be surprised to learn that techniques to improve low-power, low-RPM efficiency probably sacrifices high-power, high-RPM efficiency.
- rickycook 7y ago
  they did call out scooters and drones, so id guess you’re right
bigiain 7y ago
Possibly. You can get motors running 90+% efficiency, but only in a more or less narrow power band. If they can improve the efficiency in the ends of that bell curve, even if it's not an overall efficiency increase across the entire power/torque/rpm/"throttle" range, they might realistically be getting a 50% increase in "real world" use... Especially if they can do that in a way that removes the need for a gearbox (to keep the motor in it's highly efficient range).