I told one of my friends I wanna upgrade the 12v battery. He told me I cant do it myself. I have to let dealer install it for me. Last time he did it on his car, no lights on the dashboard came up afterward. I tried to google it, it doesn't seem people having problem with it except they lost radio setting. So, can I install it myself? When get a new battery, do I need to charge it first before install? Prius has really small space for battery [http://techno-fandom.org/~hobbit/cars/prius-12V/]. Is there any +1,400 watt battery that can fit in there without tearing and cutting? Wanna upgrade my audio system. Or should I just add another battery?
Only run your stereo in Ready mode, then it does not matter how much 12 volt battery you have. This Optima comes with detailed directions. Optima DS46B24R Optima battery $175 direct fit replacement for Prius 2004 + & Plug-in Prius with Instructions You will be fine.
