I have a Verizon Ellipsys 7 tablet that I found in the trash. Works great. I don't have the Verizon service but I still can use it on my WiFi. There is no charger so I charged it with the charger that came with my Logitech Wireless keyboard & mouse. It puts out 5V@1A. It charges up OK but it keeps telling me that the charger is incompatible, please use the original charger. Since I don't have the original charger should I be concerned?