This device from Anker is compact enough to fit in your glovebox, and powerful enough to jump start any 3L gas or 2.5L diesel engine many many times over on a single charge (Anker claims around 15 times). Surge protection and an incorrect setup alarm included for peace of mind. Almost 1,000 reviewers on Amazon rate it 4.5 out of 5 stars, reporting many successful jumps of cars, motorcycles, and giant trucks -- many with completely dead batteries (read reviews). Also includes 2 USB charging ports for your portable USB devices, and a built-in flashlight. It's typical list price of $160 has been reduced 50% to $80, making it a good consideration for yourself, or a gift for someone else's glove box/emergency kit.