> Lately I found a power bank with 10000 MAh. Just like you annihilate the whole thing ....

Mega amper hours? How big was that?

Likewise, I have once bought a „500W“ case with a power supply. The quotation marks aren't abused here, they are correct - the „500W“ was just the name of the product, the power supply in it is 250W strong.

Right in front of me I have few rechargeable batteries, of 2600 mAh. Model name? „2700“.