I have a few USB-C devices with their own chargers and I'm not sure if I can interchange them. What's confusing me is the different output values listed on the charger. From what I understand too high voltage can damage the device that is being charged and too low current can damage the charger/cable, while current above required is always fine (please correct me if I'm wrong).
For example my laptop charger can output: 20V=3.25A, 15V=3A, 9V=2A and 5V=2A. If I were to charge my power bank with it which accepts 5V=3A, 9V=2A and 15V=1.2A as input, could something go wrong? In this case if I were to plug in the power bank to my laptop charger how do I know that it's charging at the 15V=3A that it should and not at 20V?
On the other hand, if I were to charge my laptop with the same power bank (output: 5V=3A, 9V=2A, 15V=1.2A, same as input) could the power bank be damaged?