 Uve Rick's EV CalculatorSalvaged from Geocities

Instructions: Fill in the vehicle information, miscellaneous information, electrical components, environmental conditions, and vehicle weight sections. Click the Calculate button that follows. The results will transfer to the sections following.

### Vehicle Information

Either use the selector for each field, or enter the correct values directly for each of the fields below. Gear ratio below should be ratio from wheel to engine (motor), including both transmission and differential. WARNING: for listed vehicles, only drag coefficient and curb wieght are valid. You must enter the other values for your vehicle.

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:

### Miscellaneous Information

• Rolling resistance:
Note: The rolling resistance assumes LRR tires are used. If this is not 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 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 your 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 your battery is not listed above, the values for Puekert's capacity and Pukert's exponent can be determined from the battery page.
• Voltage
• Weight
• Puekert's exponent
• Puekert's 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. Enter that value, then click 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

## Top Speed

Instructions: Click the calculate button.

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

## Results 1st Gear

Instructions: Click 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 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 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 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 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 in the book Build Your Own Electric Vehicle by Bob Brant. I highly recommend this book if you wish to understand how this ev calculator works.

Disclaimer: The results above are appoximations, your actual results may vary. Information in this web page is as accurate as I can make it, but I do not guarantee anything.

(C)Uve Rick 1997-2004. Copy by permission only.