Most drivers have run into a situation at some point in their lives where the battery in their car, or the car of someone that they know, has been drained. Everyone forgets to turn off their headlights once in a while and wakes up to a dead car.
Usually, getting the car going again requires a buddy with a car of his or her own and a pair of jumper cables. Jumping a battery in this way is not particularly difficult, but it does require that someone else is around and that you have a set of jumper cables.
However, this is far from the only way to get power to a dead battery. There's also the option of a jump starter. This is basically a self-sufficient battery with its own cables that can repower your car in case of battery drainage. Some drivers prefer the convenience of this device over jumper cables, as it doesn't involve inconveniencing someone else. It's also great for late at night or remote areas where someone else may not be around, which is why many choose to keep one in their cars as a precaution.
Yet there are also downsides to jump starters when compared to jumper cables. Essentially, these devices must be fully charged in a home outlet before they're of any use. The battery will hold onto that charge, but drivers need to keep in mind that it will slowly lose power over time. The battery on a jump starter won't drain nearly as quickly as something like a smartphone, but if you haven't charged your jump starter in months and go to repower your battery, you could end up with a nasty surprise. Storing the starter in a dry cool place can help it hold power for longer, but cold temperatures can damage the starter.
This further affects the amount of "juice" that is given to the battery. The jump starter is a one-use device on each charge. Once you connect the jump starter to the battery, it will transfer all of the power it has into the battery. If that's not enough to repower the car, you're out of luck. When shopping for a jump starter, look at the peak amps that it will deliver on each jump. Keep in mind that this is the amount that will be transferred right after the jump starter is fully charged - if you don't keep it topped up with energy, it will be giving your battery a much weaker shock.
Jump starters can be a more convenient solution than jumper cables, but the owner of such a device needs to take care to ensure that they are routinely charged and stored properly.