I have a project where I'm using an android tablet to power a serial relay, the relay is 20m from the tablet so iam using a Usb C > Usb A hub and a self powered USB over cat6 extender. When the tablet is charging through the input in the usb hub all is well. However when I turn the charger off (which needs to happen from time to time) there's a small <1s delay between the supply power switching from charger to tablet battery and my relay turns off. Would it be possible to add a capacitor or super capacitor to the circuit after the hub to keep the voltage up on the extender and relay board during changeover? I found this thread

https://electronics.stackexchange.com/questions/279559/car-bluetooth-power-delay-usb-capacitor

With this diagram 
[![enter image description here][1]][1]

I have found that I can get a 1 farad 5.5v supercap for a reasonable price, would this circuit be enough, it seems too simple and I don't want to damage anything with over voltage or overcurrent. 

Thanks in advance

Tim





  [1]: https://i.sstatic.net/qhx2k.png