Uve's Electric Vehicle Calculator

Uve's Electric Vehicle Calculator

Vehicle Information

Instructions: Either use the selector for each field, or enter the correct values directly for each of the fields below. Gear ratios below should be ratio from wheel to engine, including both transmition and differential. For listed vehicles, only drag coefficient and curb wieght are valid

Type of Vehicle:
• drag Coefficient:
• frontal area (sq. ft.):
• Initial Curb weight:
• drive efficiency:
• Gear Ratio (1st):
• Gear Ratio (2nd):
• Gear Ratio (3rd):
• Gear Ratio (4th):
• Gear Ratio (5th):
• Relative Wind Factor:
Note: Relative Wind Factor can be set to 1.6.
Tire size: / R
• revolutions/mile:

Misc Information

• rolling resistance:
Note: The rolling resistance assumes that normal tires are not used. If this is the case, rolling resistance should be .015.
• brake and steering:
Weight removed:
You can enter the battery voltage or you can enter the number of batteries and click on "calculate voltage".
Total battery voltage: or Number of batteries per string:

number of battery strings:

Electric Components

Instructions: Either use the selector for each field, or enter the correct values directly for each of the fields below.

motor:
If you motor is not listed above, the values below for a, b, c, d, k, and n can determined from the motor page if you have a set of curves for the motor.
• Voltage
• Weight
• HorsePower
• Maximum RPM
• Motor a
• Motor b
• Motor c
• Motor d
• Motor k
• Motor n
battery:
If you battery is not listed above, the values for Puekert's capacity and Pukert's exponent can be determined from the battery page.
• Voltage
• Weight
• Puekerts exponent
• Puekerts Capacity
• Maximum Current
• Internal Resistance
controller:
• min voltage
• max voltage
• max current
• Weight:
• Efficiency:
charger:
• min voltage
• max voltage
• max current
• weight

Environmental Conditions

Percent Incline:%
Wind:

vehicle Weight

Instructions: The only field below you can change is the Misc weight. The web page will calculate all other fields. Then click on the calculate button.

Number of Batteries
Battery weight
Charger weight
Controller weight
Motor weight
Misc weight
Total vehicle Weight

Drag Calculations

Rolling force (lbs)
Incline Force
Tire Torque multiplier
Total Battery Resistance

speed102030405060708090
Still Air Drag(lbs)
Relative Wind Factor
Relative Wind Drag (lbs)
Total Drag Force (lbs)
Drag torque(ft-lbs)
Required HP

Charge Time

Instructions: Click on the calculate button.

depth of dischargecharge time
10
20
30
40
50
60
70
80
90
100

accelleration

Instructions: Select the gear, enter the staring speed, enter the finish speed, then Click on the calculate button.

gear:
starting speed:
finish speed:

time:

top speed

Instructions: Click on the calculate button.

 1st gear Limitation: 2nd gear Limitation: 3th gear Limitation: 4th gear Limitation: 5th gear Limitation:

Results 1st gear Instructions: Click on the calculate button.

speed102030405060708090
Motor Torque(ft-lb)
Motor Rpm
motor amps
motor volts
Battery volts
Battery amps
Range (miles)

Results 2nd gear Instructions: Click on the calculate button.

speed102030405060708090
Motor Torque(ft-lb)
Motor Rpm
motor amps
motor volts
Battery volts
Battery amps
Range (miles)

Results 3rd gear Instructions: Click on the calculate button.

speed102030405060708090
Motor Torque(ft-lb)
Motor Rpm
motor amps
motor volts
Battery volts
Battery amps
Range (miles)

Results 4th gear Instructions: Click on the calculate button.

speed102030405060708090
Motor Torque(ft-lb)
Motor Rpm
motor amps
motor volts
Battery volts
Battery amps
Range (miles)

Results 5th gear Instructions: Click on the calculate button.

speed102030405060708090
Motor Torque(ft-lb)
Motor Rpm
motor amps
motor volts
Battery volts
Battery amps
Range (miles)

The calculations above were derived from information contained in the book 'Build your own electric vehicle' by Bob Brant. I would highly recomment that you read this book if you wish to understand how this ev calculator works. If you would like to see the equations used above, click here.
Disclaimer: The results above are appoximations, your actual results may be vary.
Information in this web page are as accurate as I can make them, but I do not guarantee anything.
(C)opyright Uve Rick 1997-2004.
Copy by permission only.
If you would like to see any other calculations made or have found any errors in the calculations, let me know. Email
This site visited by people as of May 30 2004.
Main EV Page