CNET logo Why You Can Trust CNET

Our expert, award-winning staff selects the products we cover and rigorously researches and tests our top picks. If you buy through our links, we may get a commission. How we test phones

Bolt Power D28 Portable Car Jump Starter review: Bolt Power D28 fits in a glovebox, jump-starts your car

About the size of a brick, the Bolt Power D28 portable battery stows easily in a car and can jump-start a dead battery.

Wayne Cunningham Managing Editor / Roadshow
Wayne Cunningham reviews cars and writes about automotive technology for CNET's Roadshow. Prior to the automotive beat, he covered spyware, Web building technologies, and computer hardware. He began covering technology and the Web in 1994 as an editor of The Net magazine.
Wayne Cunningham
4 min read

Portable jump starters used to be a basic car battery in a plastic casing, weighing up to 20 pounds. Now, improvements in lithium ion batteries enable a new breed of jump starter, one that can fit in your glove compartment and weighs about 10 ounces. Such is the BoltPower D28, the company's most powerful jump starter, which is also designed to charge your smartphone and myriad other electronic devices.


Bolt Power D28 Portable Car Jump Starter

The Good

The Bolt Power D28 includes a cable for charging portable electronics including iOS devices, a cable for charging laptops, and the ability to jump-start a car. Its large battery can fully recharge an iPad.

The Bad

Only one USB port limits the number of devices that can be charged at once.

The Bottom Line

With its large lithium ion battery and variety of charging cable adapters, the Bolt Power D28 makes an excellent charging solution for a variety of devices, including laptops, and a must-have for cars with finicky batteries.

At 6.5 inches long, 3 inches wide and well under a pound in weight, I could easily carry the D28 around in one hand. It's a little big to fit in a pocket but would store in a car's glovebox or trunk easily enough. The D28 comes in a zippered nylon case, holding its various adapter cables, which adds considerable size to the whole package. You might want to leave all that at home and just pack what's necessary along in the car.

The brick that is the D28 fits a power switch, USB port, charging port, universal output, jump-starter output and on/off switch down one long side. There is also an LED showing its charge level, a handy feature, and a button that turns on the integrated flashlight. Along with the basic unit, Bolt Power includes a battery clamp adapter, a white multijack adapter with older and newer iOS plugs and plugs for Mini- and Micro-USB, and a universal cable with eight different plugs for different type electronic device charging ports. In addition, there are AC and 12-volt adapter cables to charge the D28.

Bolt Power D28 Portable Jump Starter (pictures)

See all photos

To charge up my iPhone 5S, I had to plug in the white multi-adapter cable (or I could have used my own iPhone cable), then turn on the power switch. To further test the capabilities of the D28, I plugged in another device to the Mini-USB plug at the same time my iPhone was connected, and both charged simultaneously.

As the D28's battery is rated at 13,600mAh capacity, it could charge up my 1,900mAh iPhone 5S battery seven times over. Likewise, that amount of power is enough to fully charge any other smartphone on the market, not to mention most tablets. The USB port outputs power at 2.1 amps, the maximum for USB 2.0 charging.

Using the universal output cable is a little trickier. This adapter will work with almost any electronic device that has a round port for charging. It includes eight different-size plugs to fit the variety of different charging ports on devices. Further, you have to know the charging voltage of your device. The D28 lets you change the output voltage of its universal port between 12, 16 and 19 volts.

I found the right plug among the eight available for a portable audio recorder, and noted that the recorder's DC input was labeled for 13 volts. Plugging in the cable, I was pleased to find that the D28 was smart enough to choose its 12-volt setting and did not let me switch to a higher voltage. These round plugs will also fit many Windows laptops on the market, making the D28 an all-around portable backup battery.

One of the D28's key features is its ability to jump-start a car. Unlike a typical portable battery backup just for charging devices, the D28 comes with battery clamps that plug into a special port in its side. It can also output a peak 500 amps, enough to jump start a typical passenger car or truck engine up to a V-8.

Bolt Power D28
With its battery clamp adapter, the D28 can jump-start even large V-8 engines. Josh Miller/CNET

To test the D28's jump-starting capabilities, I borrowed a Ford Country Squire station wagon with a 5-liter V-8. The car did not have a dead battery, so I took the positive battery cable off the battery. I attached the D28's black battery clamp to the car's negative terminal, and the red clamp to the positive battery cable. Turning the Country Squire's ignition key, the engine fired right up, as if it had a fully charged battery.

Finally, as a convenience feature, the D28 includes a white LED flashlight integrated into its end. To use it, I had to turn on the main power switch, then push and hold a second button on the side of the device until the light came on. Touching the second button again started the light flashing, with two different selectable frequencies. The flashing light would come in handy if you are signaling other cars for help from the side of the road.

The list price for the BoltPower D28 is a hefty $149, although its wide range of capabilities for charging portable electronics and laptops, and jump-starting a car, could save you a lot of time and headaches, not to mention roadside assistance fees. (This prices works out to about £92 or AU$170, should you be ordering from the UK or Australia.) However, online prices seem considerably less, well under $100.

I like that the D28 has a dedicated power switch, so you know when it is on. The LED charge indicator also comes in handy. The universal cable adapter and USB port make the D28 work for just about any electronic device you are likely to have, including newer iOS devices with their Lightning adapter plugs. However, only having one USB port in the body of the D28 may prove a limitation, especially if you want to charge two iOS devices at the same time. Likewise, there is no capability to charge Macbooks.

The flashlight is a nice accessory feature, especially as you might be fumbling around looking for your battery terminals on a dark and stormy night. One thing that larger portable jump starters sometimes include, that the D28 lacks, is an air compressor. However, its small size makes it easy to stow in any car, so you are more likely to have it handy when your battery quits.