When mobile connected to the charger LED in charger glows up where charger is not connected to power socket.What's the problem.
I don't know. Is this a problem?
Probably the mobile powers the charger in reverse direction. This will lead to faster discharge of the mobile's batery than unconnected.
As long as the charger charges the mobile when plugged into mains, I don'Ät theink there is reason to wory. Simply unplug the mobile from the charger while not charging.
Nail on the head.
Mobile phones and tablets have supported 'OTG' for a while now... it just means that the phone is now capable of outputting 5V from the USB port and acting as a USB 'Host'.
This is normally the role your computer does, this is also not normal though...
USB 'OTG' usually requires a special cable or adaptor to signal to the phone that it should behave as a 'host'... I would try a different USB cable from the mobile to charger to see what happens. This may also be the manufacturer being lazy with their design... what is the make/model/manufacturer of the mobile?
(Also... please confirm that the 'LED' on the charger is not simply being lit by capacitance in the charger... how long does the LED stay lit?)
