Why Will Future Automobiles be Electric? – The Limitations of Batteries

By John Talbot

(Under the Direction of the Lord Jesus, Prov 3:6; Col 3:17)

While I believe that future automobiles will be electrically powered I do not believe that many of them will be battery powered. Batteries have their limitations. They tend to be heavy, bulky, inefficient, and expensive, and have to be recharged at frequent intervals. Some are also hazardous, being prone to exploding. The eminent physicist Arthur Bradley converted a small pickup truck to battery operation. He used it over a number of years to commute to and from work He experimented with both thin plate lead acid batteries and deep discharge motive power batteries. The motive power batteries lasted twice as long but cost twice as much, so there was no economic advantage in using them. He found that the cost of the electric energy was negligible in comparison with the replacement cost of the batteries. The replacement cost of the batteries was approximately the same as the cost of using gasoline had been before the conversion to electric traction. The electric vehicle had a top speed on a level road of 60km/h (37.3 miles per hour), which was far inferior to that when operated on gasoline.

Newer types of batteries, such as lithium-ion batteries, have considerable advantages over lead acid batteries but are still far inferior to using electric power directly from the grid. In the past the problem with using power directly from the grid has been how to connect a road-going vehicle to the grid. The connection would have to be such as not to severely limit the mobility of the vehicle, to be intrinsically safe, so as not to present a risk of electrocution, and to have adequate lightning protection. These are formidable design requirements. My company, Talbot Electric (Pty) Limited has expended the past ten years developing solutions to these problems and we believe that they have been solved.

Batteries take up space and add to the weight of the vehicle. The result is that there is less space available for passengers and cargo. Greater weight means increased rolling resistance, requiring more energy to overcome it. The biggest disadvantage of batteries is that they have limited capacity. Recharging takes time. Battery powered vehicles are essentially suitable only for short distance motoring in level country. Take them into mountainous country and the battery will go flat very quickly. Another disadvantage of batteries is that typically in a charge/discharge cycle about one third of the precious energy is wasted in heating the battery. Some vehicles have even had water cooled batteries. Batteries are suitable only for powering light vehicles. It is inconceivable that batteries could be used to power a 75 ton combination.

The next article in this series will deal with some of the advantages of powering vehicles directly from the electricity grid.

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