Free plug-in opportunities sure help!

My best tank so far -- 866 miles and still one solid pip showing on the fuel gauge. I added a column to my spreadsheet that calculates my driving cost using what I spent on gas and what I spent on electricity and comparing that to my '05 that averaged 49 mpg. This tank saved me $13.87 over those 866 miles. However, I got lots of free electricity this time. If I'd had to pay for all the electricity my car said I'd used, I'd only have saved about $3.

But then again, because there were so many times that I had to drive just a few miles beyond battery range, my HV mpg was only 48.2 this time. Here's part of my spreadsheet. There's something weird about the 2nd row. I think I didn't get the tank full.

 

I decided to try an experiment. For that last tank, I plugged in every chance I got. That included home, work, and church, plus I think there was one charge at the airport parking lot.

This time, I'm going to just plug in at home and work (I work 4 days a week) and see what the difference is. I know it's not precise because conditions change, but it'll give me a better idea how efficient it is in hybrid mode if given a chance to warm up more often.