Several items to keep an eye on: 1) Is the car using its gas engine most of the time? If so, try EV Mode, along with B3 driving mode. This will minimize gasoline useage. 2) If you are driving in very cold conditions (below about 10-15 F) the gasoline engine will run for a while to avoid draining the battery heating the inside. 3) Again if it is cold, you may not be charging the car very quickly or very completely so you use more gas. Mostly recommend becoming very familiar with your power meter. If your needle pops onto the RPM Scale you are using the gas engine. I have noticed that a single hard acceleration will often kick on the gas engine, and then the standard driving mode seems to be in no rush to shut it down and return to EV operation. Use of EV Mode and B3 driving should get you more electric use, and less gas. 4) Lastly, you are going to run out of the battery capacity someplace around 20 miles in cold weather. So if you are running more than that between charges you are going to use more gas and get shorter mileage.