Tesla electric cars charge at a Supercharger.George Rose/Getty ImagesTesla has been accused of overstating its EVs' ranges, particularly in cold weather.EV car batteries drain much quicker in cold conditions, significantly affecting their performance.The main issue is caused by drivers heating their cabins, a battery expert previously told Insider.Tesla is facing backlash following a report that says it created a secret team to suppress customer complaints about the range of its electric vehicles.Reuters reported that the EV maker had created a "diversion team" last summer, which was tasked with canceling as many range-related appointments as possible.The report says that Tesla received thousands of complaints from customers who were unhappy with their EVs' ranges, highlighting one complaint that said the car was particularly affected by cold weather — an accusation that the company has faced before.Earlier this year, the automaker was hit with a fine of around $2 million by South Korean regulators after being accused of exaggerating the range of its cars in cold weather.The Korea Fair Trade Commission said the battery performance of a typical Tesla dropped by around 50% in the cold.But Tesla isn't the only EV maker to struggle with its range in cold weather.A study by Recurrent that analyzed thousands of EVs' estimated and verified winter ranges suggested that battery performance in numerous models could drop anywhere between 3% and 32% in freezing conditions when compared to 70-degree weather.Why EV batteries don't last as long in the coldVenkat Srinivasan, a battery expert and the director of the Argonne Collaborative Center for Energy Storage Science, told Insider's Tim Levin that the main reason batteries drain more in the cold was drivers heating their cabins.Whereas gas cars use the heat generated by their engines to warm passengers, electric cars rely solely on battery power.