## 4 Results and Discussions
### Impacts on Second Life Battery  
Figures 12 and 13 show the current and the voltage of the second life battery packs during a day under different scenarios. The addition of the EVCS load demand leads to a decrease of the SLBs charging current peak up to approximately 10% as shown in Figure 12 due to the increment of the system demand. Furthermore, the peak discharge current is also increased and when the EVCS load is applied to the system. Figure 12 also reveals that the pack size increment will extend the charging capacity of the ESS as the integral of the charging current curve for the orange and red lines (3 and 4 packs) are higher than the curve representing the EV-2P scenario. This is due to the activation of the switch reaching the maximum charge capacity of the batteries. The peak voltage of the second life battery packs decreased with the increase in the number of packs as shown in Figure 13, primarily due to the increase in the total capacity of the system and gaining a more stable operational voltage. In Figure 13, reaching the maximum voltage of the ESS is delayed by an increase in the number of SLB packs. The maximum voltage of the ESS on a full charge. By increment of SLB size to 17.55 kWh and 23.4 kWh, in EV-3P and EV-4P scenarios, the peak voltages dropped to 116 V and 111 V, respectively. This is due to an increase in capacity resulting in a decrement in voltage variations of ESS and an extension of the SLB life span.  
Figure 11: Second life battery SoC for different scenarios at various times during the day.  
Figure 14 presents the SoC variations of the second life battery packs in transient conditions during the day for different scenarios. In particular, the comparison of the base and EV-2P scenarios (both with two battery packs) indicates that adding extra load demand to the system (EV charging station load) results in a rapid discharge of the battery packs from 00.00 to 01.00. Furthermore, the second life battery packs in the EV-2P scenario would  
Figure 12: Second life battery current for different scenarios during the day.  
Figure 13: Second life battery voltage for different scenarios in various times during the day.  
be fully charged by approximately 1 h delay compared to the base scenario (which is fully charged at around 14.00). The final SoC of the battery packs also decreased dramatically from 60% (base scenario) to 26% (EV-2P scenario) by adding EVCS load to the system which could result in a significant mismatch between load and energy generation for the next day. To solve this issue the number of battery packs are increased in scenarios EV-3P and EV-4P to 3 and 4 packs, by assuming that the number of PVs are constant. According to Figure 10, by increasing the number of battery packs, the discharging curve between 10.00 to 12.00 is shifted upward by nearly 10%, and the SoC peak has decreased steeply due to the increased capacity of the ESS. Furthermore, the final SoC has increased by escalating the number of battery packs to nearly 53% for the EV-4P scenario. This suggests that increasing the SLB EES size up to 23.4 kWh would be beneficial in gaining a stable energy exchange between the components and reducing the energy generation-consumption mismatch in the proposed system. The main drawback of the size increment of energy storage system would be the increase in its cost, which might be solved by the employment of SLBs given their relatively lower price when compared with brand new batteries.