How long does it take to charge a flat rechargeable battery with my Universal Charger? It will take approximately 2 hours to completely recharge a flat battery depending on the initial battery level. Related articles Certa Smart Battery Charger - (CT5SMTBTCHA) - Manual What Does 'Skin-Only- Mean? Kogan Agora Charging Troubleshooting Can I return my item? Information for Change of Mind returns and faulty items. Power cycles can fix many minor issues with phones. How do I perform one?