I've just recently had the same problem as many of you, with a 2009 Prius -- just less than a year old and 13k miles. We took our Honda on a trip for a week and returned to find the Prius dead as a doornail! I charged it up with an ordinary trickle charger and it's run fine ever since. I don't think this would be a good car to leave at the airport when we travel out of the country for a week or more! One think I think strange: no one but Toyota sells a replacement battery! The guy at Batteries plus says this is because the battery has special venting/valving and this may be Toyota-patented. Has anyone found a reliable non-Toyota source? A little battery like this shouldn't cost $150+ that Toyota wants!