Where exactly does that 230 MPG rating come from? Based on an article over at Popular Mechanics it sounds like it is completely arbitrary and bogus to me. There are a few things to understand first – the Chevy Volt has a battery pack that can get the car 40 miles on battery alone. It also has a small gas engine that gets 50 MPG. The battery is **only** chargeable from an outlet or charging station – it does **not** get recharged from the onboard gas engine like a hybrid does. Once the battery pack runs out after 40 miles the car switches over to the gas engine. As for the EPA testing, they test a car for 51 miles and then figure out the average MPG over that 51 miles. This is based on the supposed data that a typical commuter drives their car for less than 51 miles during one day. So the brilliant marketers at Chevy are claiming 0 for the first 40 miles and then only figuring in the 11 miles left to get to 51. Yeah, I couldn’t believe it either. Here is the math for you:

- 40 miles @ 0 MPG = 0 gallons of gas
- 11 miles @ 50 MPG = 0.22 gallons of gas
- 0 + 0.22 = 0.22 gallons of gas to go 51 miles
- 51 / 0.22 = 232 MPG

I don’t know what is funnier – the crazy math here or the fact that they *generously* rounded down to 230 so they could use that cutesy little outlet for a zero!

The article did indicate that the plugin cars will list a cost per mile for the battery part, but it sounds like it will take a while to get a consistent and level playing field for the numbers so we can properly compare things.