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Why you need a batteryless jump starter (and how it works)

Unlike many jump starters on the market, this one doesn't need to be regularly charged. Here's how it works.
Written by Adrian Kingsley-Hughes, Senior Contributing Editor
A batteryless jumpstarter

A batteryless jump starter is maintenance-free and needs no charging prior to use.

Adrian Kingsley-Hughes/ZDNET

Car troubles strike when you least expect them, and the three most common reasons to call a tow truck or roadside assistance are a flat battery, a flat tire, or no fuel.

When it comes to a flat battery, numerous jump starters exist that you can attach to the battery to give it a boost to get your car going. One of my favorite brands is Noco, and the company offers a range of jump starters -- from small to enormous.

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The only catch to these jump starters is that you have to keep them charged up. And if the jump starter happens to be flat itself when you need to use it, it can take hours to charge up to the point where it will in turn fire up a vehicle.

This is where batteryless jump starters come into play. 

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Rezervo Batteryless Jump Starter features

  • Easy to use.
  • Maintenance free.
  • No prior charging is required, with years of shelf life.
  • Charges in about two minutes.
  • Short circuit and reverse polarity protect against damage if connected to the wrong terminal.
  • Features impact-resistant design.
  • Can operate on a wide range of temperatures, from -30°F to 140°F (-34C° to 54°C).
  • Starts cars, trucks, boats, RVs, ATVs, and other 12V gas engines.
  • There are three ways the jump starter can be charged up: Connect it to the dead battery (takes about 100 seconds); connect to the 12V socket using the supplied cable (about 180 seconds); connects using USB (5V 2A) (about 50 minutes).

Note: The branding on my batteryless jump starter is different from the one linked below, but the specs are comparable.

Instead of having a battery, these use components called ultracapacitors, and rather than needing to be charged before firing up a vehicle, these can be charged up from the car's flat battery in a matter of minutes.

Also: The best portable jump starters to keep your vehicle juiced

Yes, you read that right. It draws the power it needs from the flat battery. (Note the difference between a flat battery and a dead battery: A flat battery has used up all its charge but can be jumpstarted and will continue to work properly once charged. A dead battery has no residual charge left and therefore cannot be jumpstarted.)

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You connect the batteryless jump starter to the flat battery, wait while the ultracapacitors draw tiny amounts of power from the flat battery, boost it, and feed it back into the battery to start the vehicle.

Instructions for using the batteryless jump starter are printed on the unit

Instructions for using the batteryless jump starter are printed on the unit

Adrian Kingsley-Hughes/ZDNET

And it really is that simple to use -- everything you need to know is printed on the jump starter.

Also: The best car gadgets, according to auto and tech experts

Connect the red to positive, marked with a +, black to negative, marked with a - (there are protections built into the jump starter in case you connect it the wrong way), press the ON button to charge up the ultracapacitors, wait for the two green lights to come on and you're ready. (On diesel systems with glow plugs, press the GLOW button to change the way the jump starter delivers the power.)

Ready to jumo start the vehicle!

Ready to jump start the vehicle!

Adrian Kingsley-Hughes/ZDNET

Now try starting the vehicle. It's that easy!

I like these batteryless jump starters a lot, and while I've yet to have a flat battery, I've used mine to quickly and safely jump-start a lot of other people's vehicles.

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