The present study was conducted in two parts. The first section was to prepare Al2O3 water-based nanofluids for the thermal-electrochemistry experiment through a two-step synthesis assisted by a microemulsion ultrasound technique. Moreover, 0.5-2.5 wt-percent concentration (wt%) nanofluids were added into a battery cell with copper (Cu) and aluminum (Al) electrodes for an reduction-oxidation (Redox) reaction to investigate the generating power capacity between 20 degrees C and 40 degrees C. The second part derived the empirical formula of electric charge density for alumina nanofluids as electrolyte using micro-power generation experiment and dimensional analysis between functional relationships and experimental parameters. The results revealed that the mixtures of Al2O3 nanofluid and emulsifying agent at a concentration of 2.5 wt% and 40 degrees C had the highest electric charge density based on the thermodynamic activity and chemical potential of the electrolytes. The empirical formula validated and estimated the electric charge density for alumina nanofluids with an emulsifier at between 20 degrees C and 40 degrees C and between 0.5 wt% and 2.5 wt%. However, the error rates for the calculated and measured values were high due to unstable power outputs at low temperatures. The error rate was below 5%. The formula presented here was an approximate estimation model which took the emulsifier into account.