The Deceptive Simplicity: Can a Regular Car Battery Power an Electric Vehicle?

Electric vehicles, while more reliant on higher voltage batteries, still use a basic 12V auxiliary battery to power essential systems such as the radio, lights, and electrical systems. However, can this 12V battery be used to power the high voltage system that drives the electric motors? The answer is a firm no, but it's not as straightforward as it seems.

Basics of Electric Vehicle Batteries

Electric cars come equipped with a 12V battery that serves as a starting battery for the internal combustion engine (if installed) and powers auxiliary systems. This is the service battery. However, the driving force behind an electric vehicle comes from a high voltage battery, typically Lithium-ion or Lithium Iron Phosphate (LiFePo), which powers the electric motors.

Why a Regular Car Battery Can't Power the High Voltage System

Attempting to use a regular car battery to power the high voltage system would be extremely inefficient and impractical. It is not possible to achieve the required power output without chaining hundreds of regular lead acid batteries together, and even if you managed to wire them properly, it would not last long. This is because:

Optimization for High Amps

High-performance car starter batteries, optimized for high amps, are designed to provide maximum starting power in a short period. They are not suited for deep discharges, which occur when a battery is used extensively beyond its normal discharge limit. The thin plates of lead compounds that make these batteries efficient for high starting current are prone to slumping or detaching from their holding matrix when the battery is deeply discharged. This can lead to severe damage and a shortened battery life.

Deep Discharge Batteries

Batteries like Absorbent Glass Mat (AGM) and gel batteries are more resistant to deep discharges, but even they are not designed for frequent deep discharges. To ensure their longevity, users should not discharge them more than about 50% deeply without risking damage.

Practical Limitations

To power the high voltage system of a car, you would need to chain together a large number of 12V batteries, each providing around 60 amp hours before risk of damage. This severely limits the vehicle's range and can make the car excessively heavy, with ranges of 30-40 miles being about the best you can achieve. Additionally, charging these batteries must be done under strict conditions to avoid overheating and potential damage.

Modern Battery Technology: Lithium-Ion and Lithium Iron Phosphate (LiFePo)

Modern electric vehicles typically use lithium-ion or lithium iron phosphate (LiFePo) batteries due to their superior performance. These batteries offer:

Higher energy density, leading to lighter and more compact battery packs. Better deep discharge capabilities, allowing for a higher percentage of discharge without damaging the battery life. Ability to be fast-charged due to their lower thermal effect during charging.

Conclusion

While an 12V car battery is essential for the operation of an electric vehicle, it cannot be used to power the high voltage system that drives the electric motors. Instead, the EV relies on specialized high-voltage batteries, typically lithium-ion or lithium iron phosphate, designed for the specific needs of electric vehicle operation.

For anyone considering an electric vehicle, it is crucial to understand the differences between a regular car battery and the high voltage battery used in electric vehicles, as they serve fundamentally different purposes.