As it turns out, they still have to be re paired every time I power off the recalbox or the controllers go to sleep from inactivity. Frustrating as hell!

Turns out it was just this one set of controllers, they're geisa controllers called "hotso" I just got 4 more sets in the mail, and they all work with the recalbox. ill post pics in a while. but heres a link to the working ones. http://www.amazon.com/HOTSO-Wireless-Bluetooth-Game-Controller/dp/B00XKXZCFM/ref=sr_1_3?ie=UTF8&qid=1456937296&sr=8-3&keywords=hotso+ps3+controller

Same problem here, although I did get them to connect once, but the moment the recalbox was restarted, or my controllers turned off, they would be unpaired again. Anyone?? Really need help here, I tried everything that farbkasten did as well.