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For family cars we need 4x 30-50 hp units. If the motor can weigh around 7 kg it can be placed directly on wheel. Adding durable brake discs (rarely used) and 2
by arbirk 3mo ago
For family cars we need 4x 30-50 hp units. If the motor can weigh around 7 kg it can be placed directly on wheel. Adding durable brake discs (rarely used) and 2 inverters front ad back and we have the EV platform of the next 100 years
- calvinmorrison 3mo agodo we need disk brakes?
- hnav 3mo agoyou'd need close to a megawatt of engine/inverter to only brake on regen.
- zhengyi13 3mo agoAs opposed to relying solely on engine braking (or the EV equivalent thereof)? I'd personally prefer a belt-and-suspenders approach.
- SoftTalker 3mo agoYes, you must be able to stop independently in the case of some kind of total power failure in the drivetrain.
- idontwantthis 3mo agoCan regen brakes keep a car stopped? I would think that the braking force diminishes as the rotor speed approaches zero so it wouldn’t keep you in place on a steep hill, but I’m not sure.
- dcrazy 3mo agoIn my experience, it’s usually but not always enough for the hills in SF. But more importantly, regen can’t handle emergency braking (it would generate too much current and heat), and you can’t regen at all if the motor loses its path to the battery.
- SoftTalker 3mo agoGood point, I guess the motor could be engaged just enough to hold the car still on a slope but there might be heat issues doing that for too long. Mechanical brake will do that easily so also needed for that reason.
- hamdingers 3mo agoAt the very least you need something to keep the car from rolling away when it's parked.
- calvinmorrison 3mo agowell you could have really cheap drum brakes that probably would last the lifetime of the vehicle. Maybe not even hydraulic - electro-mechanical with a mechanical (E brake) fallback. even better a motor brake already is a thing. Its kinda of like air brakes, requires current to disengage and looks liek a little clutch thats slapped on the shaft or housing.
- teamonkey 3mo agoSome EV models have gone back to drum brakes. The main drawback of drum brakes is overheating, which is why they can’t be used for performance vehicles, even though drum brakes can deliver more braking power. EVs with strong regenerative braking reduces pressure on the brakes, making the heat build-up less of a problem. The main advantage of this is cost, not weight or performance, but it does show that EVs have different profile to ICE cars.
- w10-1 3mo agoMotors in each wheel eats tires. Personally, I'd rather see FWD with 1 100HP motor in a 2200-lb 4-seater under $20K US, but that will never happen as the supply is artificially constrained to create high-end cachet.