My LG G4 does not recognize an external HDD with USB OTG. Why?
If external HDD's with USB connection is high power consuming,
device cannot be recognized when connected via OTG.
Note: If the momentary power consumption when connected via OTG is 600mA or greater,
connection will be lost.
How to fix
Standard USB rating is 500mA. Please note that devices are supported if their power consumption is higher.
models from LG and competitors did not have this restriction and worked with such devices.
However, battery increase in consumption and depletion was one of the main concerns (more than four times faster than normal).
As a consequence, device may power off due to a drained battery.
such a case, the device operation may become unstable and product performance can also be affected.
Now new LG models do not support connection with high power consuming devices, in order to secure stability of product use.