Acer Iconia A1-810 (android 4.2.2) - problem charging battery after setting up

Since buying it from Argos, i have only been using it for a day and there is no way i can get the battery to charge up.  It seemed to have charged up the first time you do it before turning on the tablet to do your settings etc.  Since then, i have not been able to charge it, so used the device from main power.  I gathered that you have to fully shut down the tablet (power down) to charge properly but when i go to my tablet and check the battery status from SETTINGS app (unplug the power cable), it show seconds left on battery and even then, this number changes.   Also when the message on the SETTINGS against BATTERY say charging A/C, it shows at 94%?  Where does the problem lie?

Another thing, things did not go smoothy with my intial setting up because i made the stupid mistake of leaving the device alone BEFORE completing the Google account linking and Acer registering etc but had entered the internet password but when i went back, i panicked when i saw the lock sign...still i managed to get in and tried connecting to Net with authentication problem, eventually i gathered i had lost my internet password when i left the device which i managed to reinter.  Then later i figured how to push the lock sign away so i wasn't fully locked.  Would i be better of restarting the tablet just because first time i messed it up and may have had upsetted the battery charging function.  Is this possible or there is a known problem with Acer iconia A1 for battery charging on Android 4.2.2