I got mine low enough that it would no longer show me percentages, nor distance remaining and it disengaged SuperCruise and reduced my acceleration power. It just showed me an alert to find a charger. I was 2 miles from home when it did this. I knew I was going to be cutting it close. Using the on board Google Maps is extremely accurate on providing arrival percentage if you type n a destination. It told me that I would have 5 percent remaining when I reached my destination. I do believe it was correct!! Don’t trust the estimate on the dash. Use Google Maps if you think you’re pushing it to your destination.