A Jump Box to Jumpstart Your Car

A Lifesaver When Your Car Battery Dies

Stanley 500 AMP Jump Starter with Compressor J5C09
Stanley 500 AMP Jump Starter with Compressor J5C09. Photo from Amazon

If you've ever turned the ignition key (or hit the ignition button) and all you hear is a faint click, click, click, you may want to learn more about jump boxes, because they can reliably help you jumpstart your car when the battery is dead.

All About Jump Boxes

There are a lot of different jump boxes out there, however, they all share a few common characteristics. At the core of every jump box is a sealed lead acid or gel pack battery, which is permanently connected to alligator clamp jumper cables.

Since the battery is sealed, there is little chance of it spilling or leaking, even if you tip the unit over. The battery is also typically sealed inside a plastic housing, which further isolates it.

The cranking amperage and reserve capacity differs from one jump box to another, so while some of them hardly have enough juice to start a golf cart, others are designed to start dozens of cars between charges.

In addition to a battery and permanently-attached jumper cables, some jump boxes also include features like:

  • air compressors
  • emergency lights
  • radios
  • 12 volt accessory receptacles
  • inverters

Using a Jump Box Safely

In order to use a jump box safely, you need to follow the same basic procedure that you would for a normal jump start. If your vehicle has any special procedures, then you should follow them. Otherwise, you should connect the positive jump box cable to the positive battery connection and then connect the negative jump box cable to a good ground.

Although you can connect the negative jump box cable to the negative battery terminal, it’s safer to use a ground somewhere on the engine or the chassis.

Although the procedures are similar, using a jump box comes with an additional issue. Since the cables of most jump boxes tend to be fairly short, the jump box usually has to sit somewhere in the engine compartment.

This poses a potential hazard, so it’s vital that you make sure the device isn’t anywhere near the radiator fan, any of the accessory belts or pulleys, or placed in such a way that it might dislodge any electrical connections or sensors.

Jump Box Usage Outside Jumpstarting

Jump boxes are designed primarily for jumpstarting, but they can be used for a lot of other things. Even the most basic units typically come with a built-in 12 volt accessory socket, which can be used to power any 12 volt device. That means you can use a jump box to charge your cell phone, power your laptop, or run anything else that you have a 12 volt power adapter for. They’re also good for tailgating, camping, and other activities, since they allow you to power your electronics without potentially draining your car battery.

Jump boxes with features like tire compressors can also be used to air up your car tires, beach toys, and other inflatable items, provided you have the correct adapter.

Of course, it’s always important to remember that a jump box typically has a sealed lead acid battery at its core. So while they usually don’t leak, you shouldn’t just assume that yours never will.

Making Your Own Jump Box

Since a jump box is basically just a sealed lead acid battery with built-in jumper cables, it’s technically possible to make your own (though buying a jump box is usually cheaper than building your own).

Some repair facilities do this by strapping several batteries to a hand truck, wiring them in parallel with heavy gauge cables, and then connecting a good pair of jumper cables. This is a great setup that provides a ton of reserve capacity, but it isn’t exactly portable.

If you want to make your own jump box, the best (and safest) way is to obtain a sealed, maintenance free battery with a high cranking amps (CA) and cold cranking amps (CCA) ratings, in addition to a battery box big enough to fit it inside. The battery box is an important part of the equation due to the fact that although sealed lead acid batteries usually won’t leak if they tip over, they can (and often do) leak due to age, over charging, and other factors.

Of course, the last thing you’ll need to make your own DIY jump box is a set of jumper cables. You don’t have to permanently attach them to the battery box, but you can if you want to.

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