I buy the highest rated battery for my wifes car. Then transfer that battery to one of my projects. I'll also buy high rated batteries for my 2005 chevy. I keep one extra core around and just keep pushing the old batteries down the line. I've gotten 9 years out of a couple batteries.
If I need to buy another battery for a project, I'll buy the cheapest autozone or walmart battery. I keep a small charger on my projects.
