In many cases the jump pack won't do any good unless you know you are just pushing the battery at the end of it's life. I've seen batteries develop a dead short internally and go from fine one minute to won't even turn on a dome light the next. Called AAA and they tried to jump, but even with jumper cables the dome light wouldn't come on. Getting a new battery was the only fix.Thanks for the update, another data point in the "bad battery doing weird things" pool. The clicking was probably the starter solenoid trying to make a go of starting the engine, but there simply wasn't the juice. Cells can go bad at any point, so might be worth investing in a good lithium ion jump pack to get you out of a jam.