Connecting a portable HDD to an Android tablet...?...

[AC Question]

Hi guys. I try to make a deal with my Android. I will buy him a double USB adaptor, with two entrances, and I will try to insert into one slot the auto charger USB jack, while driving in my car using a navigation app, and into the other USB slot I will try to insert a portable hard disk USB jack. Does it works? Do I danger my tablet? Or my hard disk? Or any?... Can the hardware of a tablet to recognize/read a spinning 500GB external hard drive?
Thanks.

 

[Rukbat]

It won't work unless you use a 2 port (or more) OTG cable (one with 2 USB-A connectors and a microUSB connector) and have a mobile power supply for the external drive. The phone can't power the drive, it doesn't supply enough power.