I've owned the car for more than a year and it is the first time charging it to 100% and driving a long trip. I thought it would make it a round trip but the battery dropped to 18% after a single trip. But the number doesn't add up. It says it used 47 kWh but the battery dropped 82%. This should be an 82 kWh battery with 76 kWh usable capacity as I read. The car was produced in the US. Can anyone explain?