Jump Starter Buying Guide

Battery jump starters are nothing new, but until now, ones that worked well in our tests were sized like a hardcover dictionary powered by heavy lead-acid batteries. While great for car dealers and auto recovery services, these traditional booster packs are too bulky to carry as part of a car emergency kit. But the new generation of mini jump starters tested here use compact lithium-ion batteries. Most weigh around a pound and are roughly the size of a paperback novel. The 10 units we tested had an average price of about $90, making them only slightly more expensive than traditional car battery boosters—and a heck of a lot easier to carry.

In addition to jump-starting, these units can also be used to recharge portable devices, such as mobile phones and tablets—a function that makes them a useful part of a home emergency kit, as well. All of the units we tested had at least one built-in USB port, as well as a flashlight, and some had connectors to charge certain types of laptops.

We purchased 10 mini jump starters, ranging in price from $70 to $125, and ran four separate tests on the car batteries, using different states of charge, working down to completely dead. In the first and second test, both the battery and the jumper packs were at room temperature. For the third test, we chilled both the weak batteries and the booster packs down to 0-degrees Fahrenheit. The fourth test had the batteries cooled to 0 degrees with the jump starters at room temperature. We also tested the units to see how long they could provide power to smaller devices such as tablets and mobile phones.

When it came to jump-starting vehicles, performance between the units was nearly identical. Among our observations:

• Most battery packs could start a car battery at room temperature. It was when the temps dropped below freezing that the differences appeared. Then the Pilot InstaBoost struggled, dropping below its competitors in the ratings.

• With both the car battery and the jump starter at zero degrees, none of the units were able to jump start even the weak car batteries, let alone a dead battery. When the battery packs were at room temperature, most were able to successfully jump start a frozen car battery.

• Price does not indicate performance.

Where we did see lots of variance was in the units’ abilities to charge devices, such as tablets and laptops. The best-performing unit was the Antigravity Batteries XP-10. It provided power for three times as long as the poorest performers, which came from Revo and Noco. (Interestingly, the Revo did almost as well as the Antigravity unit in our jump-start tests.) We consider this the power-source performance to be a notable factor, as these units can keep vital devices, such as mobile phones, charged up during a power outage.

Incidentally, price turned out to be little indication of performance. While the best-performing jumper pack (Antigravity Batteries XP-10, $125) was the most expensive, the weakest performer (Pilot InstaBoost) was not the least expensive—we paid $100 for it. And the second-priciest model (Noco Genius Boost GB30, $105) came in second-to-last place in our ratings.

Recommendations
Of the 10 units we tested, we awarded Recommended status to five: The Antigravity Batteries XP-10, Spirit A8 Car Jump Starter, Bolt Power D28, New Brights Compact 12000mAH Mini Portable Car Jump Starter, and PowerAll PBJS12000R. These units provided strong jump-starting performance, along with good accessory charging options.

• The Antigravity Batteries XP-10 was clearly the best of the bunch, with two USB ports, several laptop connection options, and best-in-test device charging capacity.

• Spirit and Bolt Power’s booster packs have laptop adaptors and good device charging times, but only a single USB port.

• The boosters from New Brights and Powerall have two USB ports, but they lack laptop connectors and ranked toward the bottom in device charging capacity.

All of the jump starters we tested had a maximum recommended operating/storage temperature, ranging from 120 degrees Fahrenheit for the Pilot InstaBoost up to 185 degrees for the Bolt Power D28. While some manufacturers cautioned only against operation at high temperatures (with reduced performance as a consequence), others specifically warned not to store the units at high temperatures--and that included the Pilot InstaBoost with its 120-degree rating.

That’s a major concern: According to the National Highway Traffic Safety Administration (NHTSA), the temperature inside of a car parked in direct sunlight can reach between 131 and 172 degrees Fahrenheit when the temperature outside is between 80 and 100 degrees. In hot desert areas, the inside temperature can rise even higher.

Unfortunately, the device manufacturers were guarded on the potential consequences of storing these units at high temperatures. Complicating matters, it’s the fact that most of the units list their temperature ranges (operating or storage) in the instructions, but not on the product packaging.

The takeaway: Read the instructions carefully and check the fine print. During the hot summer months, consider storing the unit in a cool location and only taking it with you on long trips. If you are storing the unit in the car, choose a location out of direct sunlight, such as the glovebox or the trunk.