How can I find out if Fedora 20 is the cause of 2 broken phones?

edit

Fedora 20 has no control over the voltage levels in the USB port - the power lines are in the domain of hardware. I've had problems before charging an Android phone and table using a cheap USB cable. Have you tried different chargers and better quality USB cables?

I bought some genuine Samsung USB leads off a popular commercial book-vending website for pennies, and it totally fixed any charging issues I had with any device. I can still use the crappy old USB cables for data. If you've used the device lots for some time, it can also be that your battery is starting to fail. I don't know if the SGN3 has a removable battery, but if it does and you know someone who has a similar device they could try your charger and perhaps test your battery in their device to see if it charges.

You might also want to check out your laptop. If there's a hardware fault with the USB module in it, it could be handing out more voltage than it is supposed to, which might cause a hardware failure in your devices.