Box opened, turned on tablet and...strange thing...battery was down to 4%...generally a new device has more residual power...
Anyway, i charged it all night for ten hrs.
Turned on again and 100% charge.
Everything runned ok for almost two days...then my tablet started to reboot randomly under 50% charge without no reason. No overheat, no strange app, no cpu stress. Just browsing internet, using facebook, sliding app drawer.
When it rebooted again charge was at 12%. Rebooted again...charge at 62...then 32%...and so on...
Maybe a battery calibration issue. So I decided to restore to default settings. Did it for 3 times...same behaviour...under 50-40% tablet started to reboot randomly.
Rapidly returned back to the store and changed with another one.
No problems at the moment, battery drain is regular with no "jumps".
Maybe it was just a defective battery but it was a very unpleasant experience.
Hope this is just an isolated event.