• With max power capacity, two-year standby time, and quick charging it tops the list of portable jump starters we’ve tested.
• A wide variety of auxiliary charge ports power everything from a smartphone to a portable tire inflator.
• A built-in LED provides three lighting modes and an IP65 waterproof rating allows use in wet conditions.

A dead car battery is inevitable. At some point, you might leave your car’s headlights on overnight which will ultimately drain your battery. Extreme cold or heat can also cause a dead battery. Even a faulty alternator can mean trouble.

To minimize stress and wasted time with a dead battery, I always carry a set of jumper cables in each of my vehicles. Recently, I took another precaution and added a portable jump starter to each ride as well. I like this option even better because a portable jump starter is more convenient and safer to use than jumper cables, which I’ve now relegated to backup status.

Here’s why: Jumper cables require you to find someone else to assist in giving your vehicle a jump. Next, using jumper cables improperly can potentially fry your car’s electrical system or even cause a battery to explode. If you own a hybrid vehicle and want to use jumper cables, there are even more details and precautions before engaging this option.

With a portable jump starter you have the advantage of independence—no one else is needed to get your battery started. Portable jump starters also have built-in protections for almost anything that can go wrong, they come with USB ports to power portable electronics, and some even have lights that can come in handy when stranded after dark. Others include a built-in air compressor to fill a flat tire or other inflatable other items.

In a recent test of portable jump starters, I chose the Gooloo GT6000 as Best Overall for its unparalleled power capacity, yearslong standby time, and rapid recharging capability.

Also putting it at the front of the pack for me is this device’s wide variety of auxiliary charging ports, a 3.2-inch screen, a built-in three-mode LED flashlight, comprehensive safety features, and an IP65 waterproof rating. If you want a powerful, dependable, and versatile portable jump starter and don’t mind spending a bit more, the Gooloo GT6000 is a worthwhile purchase.

I own three vehicles exceeding 10 years old, and one over 25, including a daily driver 2007 Honda Element, a 1998 Fleetwood Southwind Class A RV, and a 2015 Thor Majestic Class C RV. Anyone who owns older vehicles can tell you that dead batteries come with the territory, especially with RVs that sit for months at a time. I’m also a seasonal park host in Hood River, Oregon and one of my unofficial duties is to help people with the inevitable dead batteries in addition to flat tires and keys locked in cars. I tested the Gooloo GT 6000 over several months while at my host post and logged how quickly it jump started vehicles and how quickly it recharged. I‘ve also used it to power portable devices and checked out all its features so I can confirm its status as Best Overall compared to other jump starters I tested.

The Gooloo GT6000 is about the size of a brick and almost as heavy. The front side includes an on/off and boost button as well as the 3.2-inch display that shows the battery capacity when the device is powered and error codes when needed. The error codes are also listed on the back of the GT6000—more convenient than searching through a manual to find them.

On one end is the LED flashlight and on the other is the two-prong plug for the GT6000’s 16-inch jumper cables along with a wide variety of ports. The ports are hidden behind a rubberized black cover with labels for each one in larger white type--a nice touch.

With 27,000 mAh capacity (a measure of how much energy a battery can store) and 6,000-amp peak current (the maximum instantaneous electrical current a device can deliver), the GT6000 is by far the most powerful device I’ve tested.

This can jump-start almost all vehicles that use a 12-volt battery—everything from motorcycles to heavy-duty trucks with up to 12.0-liter diesel engines. (Many of the devices I tested tap out at anything above a 6.0-liter gas and 4.0-liter diesel engine.) The 6,000-amp peak current capacity is delivered when the boost button is pressed, whereas in normal mode it delivers 800 amps per jump start.

Another great feature is its 24 months of standby time—by far the longest of any portable jump starter tested. After last using the GT6000, I noted the battery was at about 95 percent and when I fired it up after it sat unused for almost five months, the battery was still at 79 percent.

The GT9000’s wide variety of charging ports also sets it apart from rivals, including the 15 volt/10 Amp DC out port that when connected to a supplied adaptor, can be used for powering portable inflators and other devices that use a male 12-volt plug.

For instance, I used it to quickly fill an air mattress. Another handy feature is a supplied 12-volt-to-USB-C cord that can be used to charge the GT6000 from a car’s 12-volt power port in a pinch.

Its 3.2-inch screen is one of the largest of any device I tested, and the GT6000 has nine safety features that protect against inadvertent sparking, reverse-polarity, overheating, short-circuiting, overcurrent, high-temperature, reverse charge, and over- and under-voltage. The GT6000’s IP65 waterproof rating allows it to be used in wet environments and a built-in LED has three lighting modes: flashlight, strobe, and SOS. It also comes with a drawstring nylon storage bag that’s common with portable jump starters at this price.

I tested the GT6000 by jump starting several vehicles with weak or dead batteries after people had left their lights on or drained their battery for other reasons during the the season at the park where I’m the host. I never once had an issue.

A few months later, after not using the GT6000, and with about a 90 percent battery capacity, the real test came when the battery in my girlfriend’s 2017 Honda Accord was so dead the engine wouldn’t turn over and nothing electrical worked at all—and she needed to get to the airport. I hooked up the GT6000 and the engine instantly started even without using the boost button.

I found during testing that the GT6000 has some downsides. It’s one of the heaviest units I tested and is more expensive than less powerful portable jump starters that may work for most people. It doesn’t have a built-in air compressor to inflate a low or flat tire, like the Battery Tender 800 AMP Jump Starter and Tire Inflator that cost just $9 more (but has a much less powerful battery). It also doesn’t come with an AC wall charger, and the monochromatic screen can be difficult to read in direct sunlight.

That said, if you want one of the most powerful and versatile jump starters available, one with a long standby time so you know it’s always ready, quick recharging, and a large variety of auxiliary power ports, the Gooloo GT6000 is hands down my recommendation.

The cost of the Gooloo GT6000 may cause some buyers to balk and buy a less expensive portable jump starters, and frankly its maximum capacity is overkill for many motorists. But when stranded with a dead battery on a rainy night, the extra cost, power and features will be well worth it.

Buy the Gooloo GT6000