Akash Solar provides solar panel based AC systems that can function as back-up units (IPS) in urban areas which are subject to frequent power interruptions. These IPS units are charged from both electrical lines and solar panels and thus not affected by the duration of power outages. Solar IPS unit sizes range from a few hundred watts for single houses/apartments to several kilowatts for commercial buildings. Other grid-connected AC systems include solar panels with battery storage supplying high quality power (no voltage or frequency fluctuations) for sensitive loads in commercial buildings.