Batteries & Cost
In 1911 you could order a Detroit Electric with Thomas Edison's new nickel-steel batteries. Edison had been promising his new batteries for a decade and unsuccessfully tried to manufacture them numerous times before, but by 1910 he finally had them ready to go. For electric car manufacturers, this was the moment they'd been waiting for. The average mileage on a charge would go from 50 to 100! With the roads being what they were at the time, 100 miles would take you just about anywhere you wanted to go.
In fact, Detroit Electric ran a mileage test in the fall of 1910 with Edison batteries and set a mileage record of 211.3 miles on a single charge. (Chronicled in The Detroit Electric Scheme.) And then Baker Electric one-upped them in December with over 243 miles!
A 1911 Detroit Electric cost between $2,000 and $3,500, depending on the model. The Edison battery added $600 to the cost. Ouch. As a contrast, a Model T roadster cost $600 for the whole car! Of course, it was nothing - at all - like a Detroit Electric. Still, the average cost of a new car in 1911 was $1,130.
Unfortunately, batteries, whether nickel-steel or lead-acid, didn't get significantly cheaper. Gasoline automobile prices kept diving, driven by intense competition and improvements in manufacturing efficiency. The electric car companies never gained that advantage, and their prices stayed very static.
The price gap kept growing, and the self-starter for the gas cars eliminated the greatest advantage the electrics held--easy starting. By the time "The Great War" began, electrics were on the ropes. By 1920 they were all but gone. (Although, believe it or not, Detroit Electric was in business into the 1940's!)