I bought my 05 Gen II about a month ago and just filled up for the 4th time. I have wondered just how far you can go on a tank of fuel and found out the other day. I went 516.5 miles. I went 145 miles from the time the last pip started blinking. Which was great, except that I had just gotten on the interstate when I ran it out of fuel. I coasted in neutral to the next exit and since the gas station was only two blocks away was sure it wouldn't be a big deal, though it was slightly uphill. Being on the interstate trying to do 60 mph sucked the juice out of my batteries. (It took a minute for me to realize the engine was running out of fuel) Luckily I made it about 30 feet from the pump before my batteries gave out. I was nervous the engine wouldn't start but it did. So, now I know. I'll sit in my corner with the dunce cap on. Filled up with 11 gallons. Normally I can only squeeze 8 in there. I averaged 46 mpg on the bright side.
Running your batteries all the way out will have a large negative effect on their lifespan. You might well have taken a year off their expected life. Lesson learned as you say.
