I plug my fitbit in to charge and after it is completely full I took it off, not even 8hrs later with no activity, it's at 10% battery. This is already a replacement as my last one did the black screen of death for no reason as well. My 6yr old Samsung Gear 2 watch still works better to this day than my 2 fitbits have. Would like suggestions besides, don't use fitbit it is built to die after the warranty, thanks.