Jump starter or jumper cables?

Why we carry a jump starter pack, which size to get, and the small tools that turn a jump start into a real fix.

Dead batteries are the other big roadside call. Jumper cables work, but they need a second car parked nose to nose, which isn't always possible in a parking garage, a tight driveway or on a shoulder. A jump starter pack does the job by itself, so it's what we carry.

Which size

Bigger isn't just for big engines: a stronger pack also starts a battery that's been dead for days, or a car that's been cranked over and over. For most cars, the NOCO GB40 is plenty. If you only carry one pack and you get trucks, SUVs and big V8s, carry the NOCO GB150. The GBX155 is the step up for diesels and the worst cases.

Hooking it up safely

With the pack off, clamp red to the battery's positive (+) post and black to bare metal on the engine block or the negative (-) post. Turn the pack on, wait a moment, then start the car. Unclamp black first, then red. If the battery is cracked, leaking or swollen, don't jump it; that car needs a new battery, not a boost.

Was it really the battery?

A jump gets the car running, but the driver wants to know if it'll start again tomorrow. A battery tester takes a minute and tells you whether the battery is worn out, or whether the alternator isn't charging it. If the battery light or check-engine light is on, an OBD scanner shows why.

Corroded or loose terminals

A lot of "dead batteries" are really a loose or corroded terminal. Cleaning the posts and tightening the clamps fixes it on the spot. When a clamp is stuck on the post, a terminal puller gets it off without bending the post or cracking the battery.

Swapping a battery

If the driver has a new battery with them, plug a memory saver into the OBD port first. It keeps the radio presets, clock and settings while the battery is out, and on some cars it saves a trip to the dealer to reset things.