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.: sizing the battery pack

Sizing the battery pack is made far more complicated than needed - there aren't that many different options. This calculator covers the basics which probably applies to 90% of the needs. The assumptions are as follows:

  • This is for a basic automobile for daily use - not racing or cars drawing huge current (1000+ amps).
  • Lead acid batteries  - because most people don't want to shell out $10,000+ for batteries.
  • Higher pack voltage (144v) is generally advised for "normal" cars.
  • A "normal" size car with average aerodynamics, tire performance, gear efficiencies, ...etc.
  • The Range per Charge  is 300Wh per mile which is typical of a normal car.
  • There is usually little difference in a battery's 10Ah and 20Ah rating so it doesn't have a big impact on the pack size.

 
Range per charge (miles)
miles   Using an average of 300Wh/mile
Battery pack voltage (volts)
volts     Pack voltage has a big impact on pack capacity
Battery Ah rating (10Ah)
Ah   Enter ONE of your battery's 10Ah rating (or 20Ah if that's all you have)
Battery voltage
volts   Enter the battery voltage (eg. 12)

Your battery pack capacity:

Ah  This is based on the values given:
 (range * (Wh/mile) * 1.8 ) / pack voltage

Number of batteries you need:  
     This is based on your battery's Ah rating.