The answer to this question will vary across different models of electric cars for kids. With that being said, when purchasing, the charge time and running time should be clearly stated. The voltage of batteries for electric cars for kids varies from 6v to 24v. If for some reason the electric car is not running as long as it should be, there may be something wrong with the battery or the charging chord.
Generally, you’ll need to charge the battery overnight. The run time for a kids electric car once fully charged can vary from 1 to 3 hours at a time. To extend the battery life, consider keeping the electric car at the lowest speed. Most electric cars come with a battery. But, if you purchasing a second battery, you’ll be ready to swap it out once the first one runs out to extend the playtime!