Well, I just did myself in. After a series of user errors, my Prius is non-functional. My 12V battery had been showing signs of death, and finally failed to boot th car yesterday morning. Hearing of $170 toyota replacements, I checked the auto parts store and found a $80 version at Autozone. (first mistake) Got the battery into the car, but the terminals were too large. I "adjusted" the the connectors until they fit. I then attempted to start the car, but got no response whatsoever. The amber taillights were on, but nothing else. Looked at the battery again, and to my horror, the battery polarity was opposite of the OEM battery! I quickly removed the leads, then turned the battery around to connect it properly. The terminals were originally towards the interior of the car, just like the OEM, now they are toward the exterior, and the vent system can't go back together like that. Definitely not a usable battery. Once I had the leads on the correct terminals, I attempted to start the car again. The led in the power button flashed but nothing else happened. I am going into the Toyota parts department today to get a correct battery, new connectors, and whatever other parts I'm going to need. I haven't checked yet, but I suspect the big 100A fuse is dead. Any other suggestions I check out? I'd rather not make multiple trips in, as the dealership is a pretty long trip from my house.