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How to Jump Start a Car With Its Own Battery

How to Jump Start a Car With Its Own Battery

Howdy, folks. [Lawyerly garbage: the hyperlink is an affiliate link to Amazon. Shopping thru it will earn me a small commission at no expense to you.]

Today’s article is to review the Autowit SuperCap 2 no-battery portable jump starter. {Video review hitting Crossed Cannons Readiness channel in 2-3 days.} I first found this device on a very large video channel that tailors to car fanatics about three months ago. Having been recently disappointed in a battery-powered product, I was immediately intrigued enough to buy one. I was contemplating killing the battery on my travel trailer just to demo this product. While I’ve decided not to do that, just a few days ago I had a chance in real life to use this product, so I decided to tell you about it today.


To make a long story short, my son’s fairly new car sat unused for almost two weeks. A few mornings ago, he came back into the house at 4:30 AM to let me know his car wouldn’t start. It was dark and cold, at around 35 degrees Fahrenheit. I sprung into action and retrieved the new toy from the back of my wife’s SUV. So just how can this thing jumpstart a vehicle with its own dead battery?


It’s called the SuperCap, because it has not one for four powerful capacitors and a microcircuit for charging them. Unless the battery has absolutely no voltage, it will work. In the smallest electronic terms, a capacitor stores a charge. They’re able to increase voltage in electronics. Most dead vehicle batteries still have something in them. In North American cars, though they’re called 12-volt, a full charge is actually 13.8 volts. Vehicle batteries are considered discharged with as much as 12.4 volts still in them. On the morning in my story, the electronic readout immediately showed 7 volts, though it dropped to 6.5 volts for most of the charging period.


Operation was simple. I plugged the red and black leads into the device, and it turned on automatically when I attached their clips to the battery. One of the very first things I noted was that these clips opened up very wide and fit onto the post and clamps easily. The charging period took about 15 to 18 minutes, which was longer than I expected. The manufacturer claims it will work in three minutes and in extreme weather. The near-freezing temperature is certainly enough for a weak car battery to not have enough cold cranking amps. I consider it possible the cold affected the actual car battery as a possible factor. I was in my skivvies, it was cold and dark, and I left my phone in the house, so I didn’t shoot any footage. The display showed the voltage and percentage of charge in the SuperCap the entire time. It immediately charged to eighteen percent and then slowly climbed to 13.8 volts/100% the entire time. Again, there is no battery in this machine—it simply uses the remaining voltage in the vehicle’s “dead” battery.


Once it achieved a 100% charge, it beeped. I pressed the small button on the side and it began a 10 second countdown, which was displayed on the screen. After ten seconds, it beeped again, and my son was able to start the car immediately.


I consider this device a major improvement over the emergency jump start batteries. We’ve had one of those in the past, and because I wasn’t on top of charging it once per quarter, it was dead the one time I needed it. In fact, it was so dead that I couldn’t even to get it to take a charge, forever to be a paperweight. Another factor I should point out is that to do a traditional jump of my son’s car from another car, we would’ve needed to push it backwards in the cold dark morning just to be able to get the batteries close enough to be connected with traditional jumper cables. While not that big of a deal here, the portability of this device, combined with it not needing to ever be routinely charged to maintain capability, could be a huge factor if you’re stranded in an isolated or hard to access location.


Other than the long charge time, the biggest con about this device is the cost, which was about $150 in the summer of 2021. Regardless, I consider that price a small factor compared to leaving this thing alone for years at a time and it still functioning. For those who skipped around or just aren’t familiar with DC electricity—this device has no battery in it, and will only ever need to charge itself off the actual target battery at the moment of use.


This kit also comes with USB and cigarette lighter charging cables so that it can be charged elsewhere and hand carried to the location ready to go. The manufacturer gives it a 10-year shelf life with components that will survive being used 100,000 times. Their literature doesn’t mention anything about charging electronics from its charge with the use of the USB cable, so I advise against that. I will be buying two more of these. Remember, posse, our duty is to be ready.

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