Measuring System Efficiency of Using Backup Batteries From Grid Power

For my thermodynamics project, I set the depicted components up to measure the total efficiency of charging batteries from the grid then discharging them through an inverter- in my case, 110v->24v->12v(wiring change)->110v->load. This is a small-scale model of a system that would serve a household wherein the grid power is only available for a few hours per day, or intermittently. Many areas in Africa are like this. My efficiency was about 60% total. I haven't yet measured individual component efficiencies yet using the DC powermeter, that is the test in progress while I took this video.