Sustainable energy company, Gridserve, has produced some interesting figures on factors that cause the most drain on an EV battery. 

Using a combination of live vehicle data, manufacturer tech sheets and a careful calculations, the Gridserve experts were able to calculate how much energy electrical systems require. 

The single biggest drain on a battery, other than actually driving, is climate control. Systems typically require about 3 to 4 kilowatts to run, which equates to seven miles of range per hour to run the air-con and five miles per hour to run heaters. That means over a three-hour summer holiday road trip, air-con would reduce range by about 20 miles. 

Other findings were that an audio system can use 0.3 miles per hour, while an infotainment display uses 0.4 miles per hour. A USB charger is less of a worry, with a minuscule amount of impact on range. 

Gridserve also say the range is affected by conditions outside and how you drive. One way to claim back some of that battery life is with regenerative braking, which can add as much as 20% range if used wisely. 

Speed is also an important issue. Data from Gridserve found for example over an hour long journey, on average an EV will use 13% less energy driving at 60mph compared to 70mph, equal to roughly six miles of range per hour.