Battery life is a critical aspect of mobile phones. I have a 4000mAh battery and I can use my phone without charging for even 2-3 days without internet.
But I have lost the charger that came with the phone, which is having a current rating of 2A. So I am concerned about the health of my battery when I plug it into another charger or my USB 3.0 port.
I know that if a load is connected to a source, the voltage ratings of both the load and the source should be the same and the current rating of the source should be greater than or equal to that of the load. The idea here being that the load will draw the amount of current that it needs. So I can safely connect a 3V LED to a 6A 3V source and it would work.
But upon research I found that this is not the case with charging of batteries. In this case current supplied is also an important parameter. But don't smartphones have internal circuits that regulate the current that goes into the battery?
How good a practice is it to charge my phone which had a 2A charger in the box using a USB 3.0(1.5A) or usb 2.0(500 mA)? How about using a .4A Samsung charger? Will this result in any damage in the long run?