SuperCap 2 12-Volt Battery-less Portable Jump Starter (Up to 7.0L Gas, 4.0L Diesel Engine) Built-in SuperCap, No Need of Regular Charge, 10 Years Lifespan, Extremely Weather Operating

Good solid build, draws it's power from the flat battery. So if your battery goes flat and no one else is around it could be a live saver.

Hat meinen alten Diesel gestartet. Finde die Möglichkeit mit 5v Kabel zu laden auch sehr praktisch. Langlebige Kondensatortechnologie!

I thought I would own this item for a year or more before I needed it, but less than 3 days after it arrived, I found my Prius's 12V battery was too low. I got lots of info on the dashboard, but it refused to start. I'm lucky that my 2020 Prius e-AWD has the battery right up front in the engine compartment, like any other car. (My older one had the 12V battery hiding deep under the cargo compartment, behind the rear seat. That location would have made the Autowit even more convenient, compared to stretching jumper cables from another car.) I removed the Autowit and the main booster cable set from the zippered case. The other items in there are just for charging from another source if my car battery is really far gone. A flexible rubber cover protects all the ports and the power button on the Autowit. The blue plug that fits into the side of the booster is marked + and - to match markings on the unit, and the plug is shaped so it only fits one way. I didn't have to press any switch; as soon as I connected to the battery (red to red and black to black, like any other jumper cables) the unit beeped and began charging from the car battery. The display in the top edge of the front of the booster is very small, but crystal-clear and steady. I had to slow down my camera shutter to get it to show the whole display - the the naked eye it isn't blurred at all. The Prius hybrid has a much smaller 12V battery than most cars, since it only needs to fire up a small gas engine. Mine was down to 9.8 volts, low enough for the car to refuse to attempt to drive. I didn't time how long it took to fully charge the Autowit's capacitor. It seemed like forever, but was probably 8 - 10 minutes. That little display counted up 1% at a time, while it reported the battery voltage dropping slowly to 8.0V. Having that display makes it obvious that I'm waiting for it to charge, and that it's going fine. At 100% the booster beeped. The beep is so quiet (to my 70 year old ears) that I didn't try to hear the long beep that tells me the 10-second timer is up. After the "ready" beep I pressed the small red button to get ready to start (the only button on the unit), and I just counted 10 seconds while walking around to the door and sitting, before starting the car normally. And it worked! BUT THE PRIUS STARTED THE ELECTRIC DRIVE SYSTEM ONLY. The dashboard showed the car was up and running, but it was silent - it hadn't started the gas engine. I pressed the gas pedal to force the car to start the gas engine (still in Park), and it fired up and began charging all the electrical stuff. After a few seconds of running I got out and went back to the Autowit. That little display told me the car battery was now being charged at 13.8V, exactly what you expect in any 12V car system. I have AAA, and calling for a jump start would have been free, but I would have waited most of an hour at best to see my rescuer. I have a battery thing that provides 110V AC and 12V DC, but it's too small to provide the big, sudden current needed to start a car. It would have blown a fuse. I could buy a bigger battery-based jump starter, but those are big & heavy, and they need to be kept charged if their going to be any use. Maybe plug it in overnight once a month. Just fine if you start dead cars for a living, like the AAA guy, but if I never used mine, I'd forget, and when I needed it a year later, it would be dead. This Autowit is built to not need charging until it's needed, and then it charges itself off your low battery. (That's not some new miracle electronic circuit. Voltage multipliers have been around for decades. This is a perfect application for it.) If my car battery was so dead that it couldn't charge the Autowit, I could still use that battery power unit to charge my Autowit, or even my power bank for recharging my smartphone. That would have been very slow, but could save me out on some logging road, far from cell service. And I can feel better about helping others with dead batteries. Toyota warns that the Prius has thousands of dollars worth of computers controlling the engine, and connecting it to some old beater with a dead battery might kill my car, resulting in a very expensive repair after getting it towed. But I can quickly charge the Autowit from my running car, disconnect it from my battery, and carry it over the the "victim" car for a quick & easy start, without ever endangering my car with electrical noise from the other. I still need to learn why my car battery got so weak. Probably my dash cam system constantly recording while the car is parked. (VanTrue N4 3-channel system with optional GPS camera mount) Or maybe Toyota's latest software update is causing the car's computers to drain power - seems less likely. But whatever is draining my battery, the Autowit rescued me easily, automatically, and relatively quickly. I'm very glad I bought it, and it's going to live in my car for as long as I have it. *** EDIT *** I was going to contact Autowit about my ling charge time, compared to other reviewers, but decided to test it first, so I would be armed with actual times and photos. I left my car parked and off, and turned on the headlights to drain the battery, testing it with my voltmeter. When it was well below 10V I tried to start the car normally. It refused, giving me the same low voltage message I had seen before. I hooked up the Autowit and watched its display of battery voltage and capacitor charge %. Starting from 17% charge (residual from previous use, I guess), it reached 100% in about 3.5 minutes, much better than my first experience. I pressed the button on the unit, got into my car while I counted 10 seconds, and started the car. Perfect. Again, it came to life in Electric mode, so I pressed on the gas (still in Park) to force it to start the engine. I let it run while I got out and disconnected the Autowit, closed the hood, and went on my errands. Another benefit: I never saw any spark when I connected or disconnected the cables to my battery, both times that I used it. Using standard jumper cables and another car is a bit scary, because you sometimes generate big sparks when the cables touch the battery poles. Since a dying car battery often vents hydrogen gas, that's scary. The hydrogen can burn, and it it burns inside the battery, it can explode. That's not common, but it can happen, and can burn your skin, eyes, and clothes with flying sulphuric acid. To avoid that I learned early to hook up the + (red) side first, then connect the - (black) clamp to some heavy metal bracket on the engine. It's always the second connection that will spark, at either car, and making that second connection on some part far from the battery can save you from an awful mess. But that's with normal jumper cables. I never saw even a tiny spark from the Autowit cables, while connecting, or removing them.

Slower to charge on usb than advertised

I'll start this review by saying I own both this Autowit jump starter as well as their previous model. As such, I can compare them fairly well. You may have seen this product on a popular YouTuber's channel and while it doesn't come out on top, I'll explain why this technology is right for me. I live in the subarctic where winter's super cold temperatures are the norm rather than the exception. The problem with battery based jump starters in cold climates is the battery won't hold a charge while stored in your vehicle for weeks/months at negative temps. These capacitor based systems are essentially immune to this problem, since you charge them when you go to use them and also there is no battery chemistry involved. Conceptually, this unit will take remaining energy from your insufficiently charged battery - and release it all at once, allowing you to jump start your rig. It suffers with really weak batteries, but really, it just takes longer to charge. While it's true that it won't charge from a truly "dead" battery, this is really a better application for a battery charger anyway. That said, you could use the DC accessories to plug this into an alternate power source (another battery, USB or cig lighter adapter) and start a truly dead battery. When I need a jump starter, it's because it's been -40F for a week+ and I haven't started my vehicle. In fact, I've put my old Autowit through exactly that exercise more than once, down to -46F. I gladly bought this updated model for my second vehicle as it's been such a helpful and versatile tool to get through the harsh winters. I've tried this newer one out a couple of times and expect it'll do every bit of what the old model will do. For me, a tool like this needs to be operational at all times (not just fair weather) and this fits the bill nicely. There are some differences and "upgrades" found in this unit, compared to the old version. First, the cover for the plugs is a nice rubber insert, which is infinitely better at handling cold temperatures than the (now rock hard) plastic insert they used previously. The display is nice, it gives you battery voltage and general indicators of status. The buttons are a little more clear in this unit and there is no longer an "on" button, it engages when clamped to your battery. Most importantly, the unit gives you audible clues (beeping) that you can use to know precisely when to start your vehicle. That feature is completely absent on the old version, meaning it was a bit of a guessing game of when to try starting your rig. I also super appreciated the storage case that comes with. As for the bad? There's very little in my opinion, most of my critiques were corrected in this updated model. If I had to pick one thing, it's that the beeping isn't quite loud enough. It's really hard to hear (even in deafening silence) since the hood is often up and in the way of when you need that audible cue. As for the popular YouTuber that rates these - his "cold test" really needs to be multiple weeks at -20F or lower, like it might see in the real world. Overnight in freezing temperatures is nothing, not even enough to take out my battery to begin with. This is one of the only units that is suitable for this scenario. Even if you're not facing these odds, this is still the "survivalist" version of a jump starter - one you can take anywhere and jump almost anything. It's a trusty bit of kit in my book and that's why I now have two of them!