Trickle Charger Question

[KevinH1990]

Here's the battery tender I just bought:

http://www.sears.com/shc/s/p_10153_12605_02871219000P

It comes with three different types of attachments - cigarette lighter, clamps and rings that fit on the battery cable bolts. All three hook to the end of the charger using a connector.

I haven't decided which to use, but the rings that fit on the battery cable bolts looks like the best solution. I've had problems with devices that attach to the cigarette lighter popping out of my Boxster. It seems like the cigarette lighter in the Boxster is slightly smaller than in other cars.