long connector is SATA power.  short connector is SATA data.  Just get a new sata data cable to connect to your second ssd and the other end to motherboard empty sata port (black or blue), then you are all set to go. [IMAGE] [IMAGE] [IMAGE] (sata ports #10, 11, 12)  
Hi, I have two 2.5 drives I'm trying to put in the two open bays. However, there are two long connectors but only one short connector (sorry I don't know the names of these, but they are what go into the end of the SSDs). I plug a long and short connector into one SSD and that drive works fine, but that only leaves me with a long connector (no short one) for the second drive),  and so that drive doesn't work. Is there something I'm missing? Thanks!
XPS 8940, how install second 2.5 drive?