  Theoretical explorations have revealed that quantum batteries can exploit
quantum correlation to achieve faster charging, thus promising exciting
applications in future technologies. Using NMR architecture, here we
experimentally investigate various aspects of quantum battery with the help of
nuclear spin systems in star-topology configuration. We first carry out
numerical analysis to study how charging a quantum battery depends on the
relative purity factors of charger and battery spins. By experimentally
measuring the polarization of the battery spin undergoing charging, we estimate
the battery energy and establish the theoretically predicted quantum advantage.
We propose using the quantum advantage, which depends on the entanglement among
chargers and battery, as a measure for estimating the size of the entangled
cluster. We develop a simple iterative method to realize asymptotic charging
avoiding oscillatory behaviour of charging and discharging. Finally, we
introduce a load spin and realize a charger-battery-load circuit and
experimentally demonstrate battery energy consumption after varying durations
of battery storage, for up to two minutes.
