Re: what is maximum hours required to be charged Samsung Battery
Welcome to Android Central! It depends on the size of the battery, the maximum amperage of the charger, and the available current from the power source. A charger with low maximum amperage (e.g., 0.5 A) will take longer to charge to full than one that's 2.0 A. Charging from a computer USB port (which provides low current) will take longer than a wall outlet.
Re: what is maximum hours required to be charged Samsung Battery
And, unless the battery's been virtually killed (use it until the phone shuts off, give it 15 minutes, turn the phone on until it shuts off, etc.) 7 hours should be more than enough. But leaving it plugged in longer won't hurt it - charging stops wwhen the battery is fully charged even if the charger is still plugged in. (I've had phones that I put on charge and forgot for months. No problem except to the electricity bill.)