For those of you if your like me (with Nexus 5) and can not get simultaneous charging while using usb OTG this might be the solution we are looking for.
https://www.kickstarter.com/projects/1094775787/port-power-usb-at-the-same-time?ref=live
https://www.kickstarter.com/projects/1094775787/port-power-usb-at-the-same-time?ref=live