Hi, I am currently undergoing a project to build a mobile power bank. I will charge a 12v battery via a solar panel then charge a phone from the battery. I am at the stage of trying to get a phone charging via the battery and I am getting a stable 5v output from the regulator. However it is still not charging the phone and when measuring the current it seems to keep dropping down rapidly, I have posted a picture below. Can anyone help or give me some advice please?