It's always a terrible sinking feeling when you turn the key in your car or truck and hear the engine fail to turn over. By the time you're in the driver's seat, you've already got somewhere to be, and this scenario means those plans are suddenly on hold. That might cause you to be late to work, miss a flight, or be unable to leave your home in an emergency. In some cases, you'll be able to grab a pair of jumper cables and give your battery a boost from another nearby vehicle, but that's not always possible, and it's certainly not the most self-reliant solution. This is why we're big believers in adding portable jump starters to the emergency kits in your vehicles.
Jump starters, or jump boxes, are essentially portable battery packs that can deliver a sudden jolt of cranking amps to start a car that has a weak battery. Each comes with a jumper cable attachment that connects to the battery terminals, and many of them include additional features such as a flashlight and USB output ports for charging small electronics. They can be built around common lithium-ion power banks, traditional lead-acid batteries, or other forms of tech such as supercapacitors.
In the following 20-minute video from the Project Farm YouTube channel, the host bought eight different jump starters and evaluated each of them based on a variety of tests. These include bench testing on a meter, starting a pickup truck with a weak battery, turning over a diesel tractor engine, and performing in freezing conditions. As with his previous experiments, Project Farm clearly states that he wasn't sponsored by any of these companies, and presents the results in an objective manner before sharing his conclusions.
This test serves as another example that big, heavy, and expensive doesn't necessarily mean effective. Some of the least expensive jump starters in the test performed the best, while also fitting into a small package and including helpful extra features. However, that wasn't always the case — a few of the cheaper units failed miserably. Overall, we agree with Project Farm's conclusion that lithium-ion jump starters are a good way to go. I carry one of them in each of my own vehicles, and although they haven't been a literal lifesaver, they've saved me from waiting for roadside assistance when my car's battery died on a 116°F summer day.