I'm planning to change out my car battery. I haven't done this myself in at least 20 years and back in those days, removing the battery generally meant your car stereo locked and you needed a code to reactivate. Nowadays it seems that doesn't really happen, but instead all the car's options will probably reset to factory defaults. This would be annoying.

I was reading that you can buy a battery tender - a 12V-producing device you clip on to the two cables that go to the battery so that when you disconnect the terminals, you still get 12V going to the car's electronics. So I was wondering: I have a jump starter/USB power bank thing (similar to this one). Can I use that to do the same thing? The only difference is that for car starting you're supposed to connect one side to the positive battery terminal and the other to the car's frame, whereas in this scenario I'd be connecting positive to positive, negative to negative.