Customer premises grid-tied Battery Assisted PV Systems can be an effective demand-side load management measure. At the same time, they can considerably lower the monthly retail electricity charges of their owners. In order to encourage end users to employ such systems in their premises, quantification of resulting benefits is imperative. In this paper, customer savings from a 2 kW/8.8 kWh Lithium-ion battery with different PV system sizes are quantified with respect to two Salt River Project (SRP) Time-of-Use (TOU) tariff plans. A 40% peak shave target is assumed. Results do not indicate significant increase in savings by adding the storage component to a 2 kW PV system. However, it was observed that PV size could be reduced by atleast 40% if the proposed battery was added to a 4 kW PV system to obtain the same benefits.