The new battery is on order, but in the mean time I’m thinking that something like this might be a decent way to keep the current battery topped off. On my recent three-day weekend the car sat for two days and was a little slow to crank on the third day. Today the electrical system seemed to reset itself, as evidenced by the clock going back to its default time; I thought the car didn’t start because I didn’t push in the clutch, but it seemed to be more severe than that. And when I went on vacation a couple of months ago I came home to a flat battery that might have been OK with something like this.
I like the idea of the lighter plug, but since my power socket doesn’t provide power when the car is off I suppose that I would have to find another way to hook this up; I think the alligator clips would be a bit of a pain, especially during winter.