Oo talaga dapat fully charged bago gamitin, lalo na pag pumping ka ng matagal or frequent throughout the day! A few of us mums tried using it half-charged and napakabilis maubos, tapos nag-struggle pa sa suction kaya hassle lang. I always charge mine the night before at may power bank din ako as backup pag out or sa bahay lang, mas safe na yan para walang abala sa feeding schedule mo.