Both my children got Fire HD 8 tablets for Christmas 2017. One has had serious battery drain in the last couple of days yet the other is fine; same setup and restrictions etc so cannot understand what’s happening. Last night before bed I even put it on to charge (which we’d never normally do) as it had totally drained again...it had started charging so i was goin to leave ot overnight yet this morning it was completely switched off and had to be unplugged and replugged in to make ot boot up again (at 0%). Any help???????