You can add calculated column TotalTime in Google Sheets/Excel with formula =PrevTotalTime + CurrentTime - if(PrevTime < CurrentTime ; PrevTime ; 0)
If you don't understand - post your csv and I will do Google Sheet for you.
I struggled but finally got this to work. To add some clarification I've broken it down into steps.
1. Open your track data .csv file in a spreadsheet editor like Excel, Numbers or Sheets.
2. Add a column after 'Elapsed Time (ms). Name it something like 'Total Time (ms)'. This header is your first cell in the column (C1).
3. In the second cell of your new column (C2), enter the value of the second cell in the 'Elapsed Time (ms)' column (B2). You can use a function: '=B2'.
4. In the third cell of your new column (C3), enter this formula: '=IF(B3≥B2,B3−B2+C2,B3+C2)'. Drag this formula to the bottom to populate all cells.
5. Save your file and add it as an input file in RaceRender.
You should now have a file that includes a column with your total time in ms, which can be used in RaceRender to accurately display values such as SOC, battery %, throttle position and more throughout the entire session.