Car Jump starters are essentially of two types. Jump Boxes and plug in units. In a nutshell, the Plug in units are essentially your car battery chargers that are capable of providing high burst of energies to start the engine motor in a go, while jump boxes are sealed maintenance free batteries that are attached to long jumper cables to do the same job. A plug-in unit is a good option if you have to charge your car batteries only at your home but you have to opt for a jump box if you want a portable one.
Most plug-in units provide trickle charges between 2amps and 10 amps with multiple settings. This is done to maintain a better battery life wherein the battery is charged at a slow speed via a low amperage. This may not be always convenient though as you may not have the time for the 2 amp charger to charge your car battery. Keeping his in mind some plug-in units have been provided with a start setting that delivers much higher amperage. With this mode you can immediately crank up your engine depending on the charge in your car batteries. This instant charge may give you an instant temporary solution to the situation but harms the battery and shortens the battery life. So it’s always worth giving it some time to charge up. If you are opting for a plug-in unit then go for the one which has multiple charging modes, multiple amperage settings and a float charge option.
The major drawback of the plug-in unit is that it has to be plugged in to an AC socket to turn it on. Although you can now find compact, small and portable plug-in units but you have to plug them in to get going.
The essential difference between the plug-in unit and the jump box is that the jump boxes are way more portable and easy to handle and are not required to be plugged in to do their job. But there is a drawback with the jump boxes as well. They cannot charge a completely dead battery. A jump box is basically a maintenance free battery sealed in a plastic molded box. They are permanently attached to heavy duty jumper cables. The jump boxes are portable and you can carry them everywhere and anywhere and with one of them around you do not have to worry about getting stranded due to a dead battery. The generally have a high peak and cranking power which will give the initial energy to crank up your engine. Though this may seem to be of real help its always wiser to charge up your batteries once you reach home. Driving along with a dead battery and jump starting them whenever you need shortens the life of the alternator. Also as mentioned before these alternators are meant to maintain the charge and are not suitable to charge up a dead battery. Another advantage withe these modern jump boxes are that they provide you with alternate features like additional USB ports for charging other devices, LED flashlights to simplify your work in the dark, radio to enlighten your mood when you are stranded. You need to check the peak amps and cranking power before investing in one.
Ideally you should have one of each type, jump box to crank up the engine in case you are stranded in the midst of a trip and a plug-in unit to slow charge the batteries once you get back home.