Consumer Reports recommended the Black & Decker Simple Start in a 2012 test of portable car battery chargers. It also found that the Schumacher e-Charge EC-4000 functioned, but did not give it a recommendation.
Consumer Reports tested four portable battery chargers and found that only the Simple Start and the e-Charge actually worked on all of the vehicles tested.
The Simple Start was recommended, as it charged according to the manufacturer's instructions in all of the tests. Though the e-Charge worked in its tests, it required more charging than the manufacturer's instructions in some cases, and some of the models provided came with dead internal batteries that would not take a charge. Both products use lead-acid batteries that can be recharged, though they cannot be stored without charging for too long or they lose capacity. They also weigh over 4 pounds each and require some trunk space to transport.
Consumer Reports also tested two smaller chargers designed to fit in a glove box, the StartMeUp2 and the Porta-Jump PJR-STH. Both models only worked to start one of the vehicles that they tested. The StartMeUp2 is also nonrechargeable and good for only one use.
The magazine concluded by indicating that none of the chargers were superior to keeping 12-foot jumper cables with a gauge of at least 4 on hand and finding another vehicle to jump-start the battery.