I have used it twice on a car whose battery had died (Renault Clio petrol) and both times it managed to start it without any difficulty.

It was tested on a Kia Sportage 1.7 diesel which had been left with the sunroof open all night. I connected the cables, left it for 30 seconds to "boost" the battery a bit, the starter struggled a little but it started! The durability over time remains to be seen...

I use it to jump-start cars that have battery issues! It works perfectly!

Jump starters have now made their way into the market and many manufacturers have released several models with costs starting from around €30 and increasing depending on the model. After extensive research on the internet and watching comparison videos mainly from outside Greece, I saw that buying a jump starter requires a lot of attention. Several expensive models fail to start engines. After much searching, I realized that the amount of amps the starter draws during engine start plays a significant role, rather than the engine size. Each person needs to research their own engine first, understand its starting requirements, and then see what kind of jump starter they need in order for it to work properly. I have a German engine with a 1.4-liter capacity and a 55ah battery. The car has been idle for about 1.5 months and the battery is completely dead, not even the dashboard light turns on. So, it worked exactly as I wanted. I connected the cables to the battery, turned it on, and immediately, power flowed into the car's circuit. The engine started right away on the first try. Not like a fully charged battery, but it turned easily and started immediately since there was no damage for the engine to stay idle. I didn't immediately try to put it in gear to see if it has the endurance to start again, to be honest. However, it did its job successfully. I will definitely use it again and write my impressions.