Electric cars

[LabR@t]

When you drive a normal car it is charged the battery right?

Why can't worries cars charge themselves as they drive?

 

[montymint]

Because you'd never get enough energy back. Laws of thermo-dynamics n all.

 

[loftie]

They do.

 

[dlockers]

Follow up - why can't I pay a credit card off with a credit card, rinse and repeat forever? Free money?

 

[JRS]

When you drive a normal car it is charged the battery right?

Why can't worries cars charge themselves as they drive?

Lots do, through regenerative tech (using the motors as generators when slowing down). Unfortunately for perpetual motion fanatics, there's this pesky thing called 'physics' getting in the way of recovering all of the energy used to gain motion in the first place

 

[Malevolence]

 

[Russinating]

As above. I've even seen mine go up a % when going down a very long hill!

 

[dlockers]

As above. I've even seen mine go up a % when going down a very long hill!

Driving south presumably?

 

[LabR@t]

Is it just a case of lacking effective energy capture

 

[LabR@t]

Follow up - why can't I pay a credit card off with a credit card, rinse and repeat forever? Free money?

Technically you could if your credit line was infinite

 

[JRS]

Is it just a case of lacking effective energy capture

No, it's (partly) a case of a portion of the input power being turned into sound or heat, whether that's from the motor or the tyres or whatever transmission the vehicle is using. And you aren't recovering that.

The first and second laws of thermodynamics also say 'hi'.

 

[Nasher]

Just needs a nuclear battery in them all then they would have power for 100s of years. I don't see what could go wrong.

 

[keyser]

Why do electric cars need a standard 12volt car battery?

 

[Graetzbridge]

Why do electric cars need a standard 12volt car battery?

Wipers, indicators, etc

 

[keyser]

Wipers, indicators, etc

pfft I want 400Volts minimum going through my wipers.

cant they transform down to 12V off the big battery?

 

[Diddums]

Is it just a case of lacking effective energy capture

It's all about rolling resistance, kinetic energy losses, thermal losses, wind resistance and a multitude of other factors. If someone managed to create a car which generated enough energy to sustain itself indefinitely, they'd change the world overnight and would be Oprah rich within a month.

 

[Graetzbridge]

pfft I want 400Volts minimum going through my wipers.

cant they transform down to 12V off the big battery?

Yes, not a problem.

 

[paradigm]

pfft I want 400Volts minimum going through my wipers.

cant they transform down to 12V off the big battery?

The issue is mainly parasitic drain from ancillary systems when the car is off. That and the fact that when the car is off, the HV battery is physically disconnected from the driveline with contactors. You’d rather ruin a “cheap” 12v battery by draining it too low than ruin your £15,000 HV pack.

 

[Deleted member 66701]

When you drive a normal car it is charged the battery right?

Why can't worries cars charge themselves as they drive?

People ask me this all the time about my ebike "so does it charge while you pedal". These people also get a

 

[Deleted member 66701]

Why do electric cars need a standard 12volt car battery?

Most dont now. They have a step down converter that uses the main battery for 12v systems (some are now even using 24v and 36v systems).