This research aims to illustrate the optimal functions of removing copper ions in aqueous solution by the electrocoagulation process in which portable solar power generators are used as renewable energy. A solar photovoltaic cell (PV), producing approximately 48A current intensity for 4–7 h per day, which was sufficient to charge the lithium batteries completely during the day. This system was connected directly to the electrocoagulation tank. The Box-Behnken design (BBD) was applied to evaluate three effects of process factors: current density, the dose of electrolyte (NaCl), and application time. The results showed that an optimal efficiency of 99.01 % Cu removal plus an energy savings of 1.039 kWh/m3 was carried out at a current density of 4 A/m2, the dosage of NaCl (electrolyte) of 1.87 g/L, and electrolysis time of 10 min. The chemical components of the sludge produced under these optimized conditions were determined by EDX. It is illustrated that the copper ions were the main elements of sludge, and nonhazardous compounds were contained. The PV-lithium battery system is considered to be an efficient alternative energy source toward sustainable development.