Did your Google Nexus 7 experienced don’t turn on even you have been charging it for hours? and while charging, there is no icon showing up in the screen too? And are you thinking either the cable or the connection cable or even the tablet has been broken? Are you considering a return to Google for repair? Then wait a sec. Try the following easy method before going any further.
Press and hold the power button for at least 1 minute.
This is to reboot the tablet and should solve the problem for most people. My hypothesis is just like the laptop computer, if you leave your machine in standby mode but drain out of battery completely, you will be prompt to the Windows safe mode next time when you plug in the power supply. Similarly, if you leave your Nexus 7 in standby mode for days but not connecting it to the power, all the power will be drained. But your Nexus 7 is in standby mode where there are many programs still running behind, and unlike the setting in Microsoft Windows, instead of going to the safe mode in the Android Jelly Bean, we will need a manual reboot of the tablet.
I have no idea how much effect will be negatively imposed to the lifespan of your Nexus 7 if the tablet need frequent reboot like this. Somehow it also indicate the battery charging-discharging cycle is not idea. To keep your tablet last long and be portable for years, it is best to power off the machine when you are done in the day and charge it before completely drain. There are good battery monitoring apps in the market that can help too.