This thesis presents technical and economical analyses for using second-life batteries, retiring out of electric vehicles, in residential solar storage in Pakistan. The feasibility of adding second-life batteries to existing residential solar PV projects in Pakistan is discussed, using the return-on-investment on the battery and inverter costs. To maximize the return-on-investment, an optimal battery control algorithm (that considers the battery degradation costs) is designed to reduce the electricity costs to a residential user by an “optimal" charging and discharging of the batteries. The algorithm requires day ahead load forecasting of the residential load, and therefore, this thesis also presents a comparison of modern neural-network based short-term load forecasting techniques. We also conduct a thorough review of the available literature on technical considerations and parameters of second-life batteries, along with an in-depth review of the use of second-life batteries in grid and residential applications. For the analysis, we assume that second-life batteries cost 50% of the new battery costs. Out of the 100 cases of battery addition evaluated in this thesis for three sizes of residential households in Pakistan, it is found that the majority of cases are financially unprofitable. The thesis draws the conclusion that due to a competitive grid feed-in tariff, solar PV installation alone can provide sizable savings for residential users.