Autowit Super Capacitor Jump Starter, 12V Batteryless Portable Jump Box, Jumper Cables for 8.0 Gas&4.0 Diesel Car, Portable Jump Starter for Car Battery, Bulit-in Supercapacitor, No Need Pre-Charge

I presented a tough scenario for the Super cap 2 to prove itself on a low battery located under the rear seat of a gm car.And it did not work as advertised, utilizing the Super cap 2 alone failed in the above scenario on the first attempt.I then connected car #1 to car #2 using jumper cables and was able to get lights and alarms to power up but still not enough juice to start it.I then added in the Super cap 2 to a location under the hood for normal jump assist's and then the Super cap 2 was able to provide just enough additional energy to turn the engine over so it would start.The ProsThe tech behind it makes sense instead of using lithium batteries it uses Capacitors for storing a Pre-charge of energy and it should work on something that wasn't so depleted maybe where you have dim lights and the dash lights up but doesn't have enough juice to turn over the engine.Unlike a Lithium battery this unit can be 100% pre charged in less than 10 mins.While it wouldn't start the car alone it did tell me the system voltage and that the battery was low, when the car was running it does display the charging systems voltage output.I did have to also use the accessories to pre charge it in car #2it comes with a nice carrying case a USB cable as well as a cigarette lighter socket plug mechanism for pre charging it.The Red and Black cable attachment is removable and is designed in such a way that you cant accidently install it backwards.The consI felt it doesn't work well with GM side mounted battery terminals, due to the batteries design the clamps kept wanting to come loose, maybe some sort of offset shoes should be included for insertion between the actual battery terminal and the cable then the clamp's could connect to the shoe instead of the small cable attachment bolt.The instruction manual is really vague on what to troubleshoot it did show a chart on the various readouts but then nothing to suggest what each one meant and how to correct them.Update:I had a no crank but the lights came on and this device was abler to operate properly and was able to provide enough current to start the car.

Update: 2 years later and I had a dead battery this morning on a Honda CR-V. I pulled this out, dusted it off, and it worked flawlessly. I haven't had to touch it, maintain it, charge it, or anything else in the meantime. I was able to just forget about for years and then it was ready to go when I needed it. Highly recommended!Original:The killer feature of this device is that you can keep it in your vehicle all the time and it is ready when you need it. I've had a battery jump starter for a couple of years, but it spends most of its time in the house so I can keep the charge topped up. I've run into people who needed a jump, but I didn't have the battery with me.This is also perfect for anyone with a hybrid vehicle that wants to be a good samaritan, since you are not supposed to jump start other people from most hybrids. From what I've read, it's not really a good idea with many non-hybrid cars, either, since jump starting someone can damage your electronics in modern cars. Having this in your car means you can still help people out without worry as well as having it for your own use.I have used this three times now, in addition to a couple of practice runs (one for me to learn how to use it, one for my wife):1. An ATV with a weak battery. I wasn't sure if the small battery would be enough to charge with, but it worked fine and only took the usual couple of minutes. Started right up once charged.2. The day after my wife learned how to use it, her friend left a car door open on her Prius and ran down the 12V battery. Despite being a hybrid with plenty of juice in the main battery, it will not start without the 12V battery. It was run down so far that the SuperCap 2 could not change, so she charged it up on her CR-V and then transferred it to the Prius and it started right up.3. My dad's old F-150 with a V8 wouldn't start due to an old battery. I went over and it was a textbook use of the SuperCap 2. There was still plenty of juice to charge with, then the truck started right up. I was curious to see it it would have enough power for that big engine, but it started right up. I drove it right to the shop and confirmed that the battery was shot and got it replaced.Couldn't be happier with this. I keep this one in my wife's CR-V (it fits in the compartment with the spare tire) and I plan to get another one for the new truck I currently have on order.