Laptop crashes when I unplug the cable. Why?

I've had a new battery in my laptop for a couple of days now because my old battery has barely lasted an hour. Now I have the problem that the laptop crashes as soon as I pull the cable out. Sometimes it lasts a few minutes, then it crashes. Without a cable, he does not even go.

What can this be?

The "new" battery is defective. Either he is older than the one you replaced, or he has a build error. Swap it.