Gauging Your Range

All plug-in vehicles, hybrid or full electric, have a meter on your dashboard that shows the current level of battery charge and an estimated number of miles you should be able to drive.  In this picture, my Bolt's battery is fully charged (indicated by the green bars on the left) and I'm estimated to be able to drive 265 miles. My Bolt also offers me a minimum and maximum range.

To understand what these range numbers mean and how they are calculated, you need to know a few things:

1. Range is estimated on your driving habits and conditions that the car has learned over the past few trips. For example, if you have been driving on the freeway a lot, it will likely calculate a lower mile range because driving at very high speeds is less efficient (much like when you drive your gasoline car at very high speeds and your miles per gallon goes down). Conversely, if most of your driving has been around town at 30 – 50 mph, it will calculate a higher range.


2. Climate control settings will directly affect your range because the electric batteries supply power for everything. Case in point, today we witnessed our range drop 20 miles almost instantly when we turned on the air conditioning. While this may sound scary, the real-time feedback makes you more aware of where your power is going and allows you to maximize your efficiency. If we had decided to turn the air conditioning off, the range would have increased again.
   
   In Minnesota, we have weather extremes: -20 degrees in winter to 90 degrees in summer. This can also cause large swings in your range. In winter, a lot of power is needed to provide heat for the passengers, defrost the windows, and thermally manage the batteries. Over the past 4 years with my Volt, I have come to expect a 20 – 30% drop in range when the weather is below 30 degrees. I have yet to see how the Bolt does this winter.


3. Minimum and maximum estimated ranges. These seem to be a straight 20% above and below my estimated range. In theory, this is informing you that if you drive better (no heavy accelerations, hard stops, fast speeds) you could potentially meet the max range, and if you drive aggressively and have climate control settings really high, then you could potentially get less. However, I'm not sure how useful or realistic these numbers will be. What if my driving conditions are already excellent? Would I really be able to squeeze more miles out of it? This is something I will have to test and provide a future update.