Why is phone charging differently with different chargers (even if they have the same specs)?

A

AC Question

I have a Lenovo k3 Note, it came with a lenovo charger that reads 2V, 2000mA for output. Since I bought the phone from China, I bought a new charger to have the plug compatible with my outlets in Italy. I bought an amazon basics charger with an output of 5V, 2100mA.

After noticing that the phone was charging really slow, I downloaded the Battery Monitor app for android to find out that with the original lenovo charger it charges at around 1850mA, while the amazon charger charges at around 1/10 of that (170-190mA). I returned the amazon charger think it might be broken, but when the new one came in battery monitor is now showing a current flow of 0mA.

Why does this happen? How can I fix this? Is it that the phone is somehow "blocking" current flow from a third-party charger?

thank you very much!