One thing that could be affecting your range is the outdoor temperature. What's your location? As it gets colder, your range decreases, and your tires will lose pressure. Try airing them up to 40 - 42 pounds cold. You said the tires are practically new - were these replacement Bridgestones, or another brand?Tires are practically new. Alignment is good. Pressure is good. I keep them at 35psi cold according to the sticker. I've read some people say to push it to 40psi. Have not tried that yet.
I don't know how old the normal car battery is. How would that effect the 17.1kWh pack?