I finally broke down and bought a $30 portable jump starter
My car battery died last Tuesday in the Hannaford parking lot in Kittery, right as I was trying to leave with a full load of groceries. I had to call my brother to come rescue me, and he showed up with one of those compact lithium jump starter packs. He talked me into getting one for myself, so I ordered a basic model off Amazon for 30 bucks. It's about the size of a thick phone and holds a charge for months. I used it yesterday when my neighbor's truck wouldn't start in the cold and it fired right up on the first try. Has anyone else had good luck with those things, or do they wear out after a season or two?