autowitSuper 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 #3: Have not needed to use it since last edit but it connects & loads up using any & all of the included connectors. I’ve even used my little 10w USB solar panel. (Took forever for reasons obvious). All worked & when I tested each, used the truck & it was ready to go. So no issues. Works as stated. Works well. The only variables are the vehicle & the user. Aside from a tiny solar who-cares-what-you-have-going-on-today panel, each method you use determines your charge time. It’s math. It works. Buy it. Just double check your connections like I didn’t. Wink-wink.Vanlifer tip for those with steeds & iffy electrical systems: Load it with your USB pack whenever you park. If you occasionally need a jump but think often enough you might need one every time, this practice will ensure less downtime when you have to go but ‘Damn! Three days since last jump. Trickled down to 20%, USB battery, yikes! I’ll be on the road in forty five minutes, not 2.5! Damn damn! :insert Doc Brown facial expression: So, shortly; Have a weak electrical system? Buy this & habitually connect it to your USB battery pack on parking. Less downtime.Update #2: I gave it a day. Out of frustrated fairness, I gave it another go. Connected to a charged battery this time. Used only the jumper connector to turn it on. Worked. Seems intermittent. Unsure of cause. Will continue use as needed & update review as my experience evolves.Update #1: It’s been a few short months & it no longer works. It will charge but not begin the countdown when the button is pressed. Damn waste of homeless guy funds!Original review below:The BEST thing about this is that it will crank a light truck. Others I looked at won’t work very well with even my little 4.6L motor. When I was experiencing an electrical issue, this helped me stay moving until I found the issue.It’s light, so easy to stow, carry, and retrieve out of your VEDC.Simple to use. Very few connections. It’s literally plug (or pinch) & play. & in the event you have a tragically low battery, you can even prime this thing with your cell phone charger or a portable USB battery. Takes longer but it works.One-person use with a ‘beep’ loud enough to hear inside your car if it’s freezing outside while you wait for it to charge.And it’s tough. With no battery in it, you don’t have to worry about handling it like you would a lithium ion or a lead acid battery jump starter.