Calculate the battery capacity for an electric vehicle based on power, time and output voltage

[PhysicsTest]

Homework Statement

If an electric vehicle needs to provide 400HP for 1 hour and the vehicles battery voltage is nominally 300V, what is the absolute minimum rating of the battery capacity in Amp-Hours (1HP = 750 W)

Relevant Equations

Capacity = Current * Discharge Time

Battery Capacity = Current * Time
Power = 400 * 750 = 300000 Watts
V*I = 300000
I = 300000/300 = 1000 Amps
Battery Capacity = 1000 * 1 = 1000AH. Are the calculations correct? Why the battery capacity is defined in Amps?

 

[anuttarasammyak]

It seems OK.

Why the battery capacity is defined in Amps?

Not Amps but AH with V given as you got it.

 

[haruspex]

AH (Amp-hours) is a measure of charge. 1AH=1A*3600s=3600 Joules.Coulombs.

 

[Lnewqban]

Why the battery capacity is defined in Amps?

The battery capacity is defined in A.h or ampere-hour.
Just like a water tank accumulates volume in gallons (ready to flow out), a battery accumulates charge in coulombs (ready to flow out as well).

Please, see:
https://en.wikipedia.org/wiki/Coulomb

https://en.wikipedia.org/wiki/Ampere-hour

"The SI defines the coulomb in terms of the ampere and second:
1 C = 1 A × 1 s.
The ampere is defined by taking the fixed numerical value of the elementary charge e to be 1.602176634×10−19 coulombs."

 

[jbriggs444]

AH (Amp-hours) is a measure of charge. 1AH=1A*3600s=3600 Joules

Coulombs, surely. Or, equivalently, Joules per Volt.