Here's a pattern I often use to read and combine multiple files with a similar structure:
library(tidyverse)
library(readxl)
f <- list.files(pattern="xls$")
TOTAL <- map_df(f, read_excel)
A base R version would be:
TOTAL <- do.call(rbind, lapply(f, function(file) read_excel(file)))
Note that rbind will throw an error if the files don't all have the same column names. On the other hand map_df will combine all of the files, regardless of the column names. For example, run the following and see what happens:
rbind(mtcars[1:5,], iris[1:5, ])
list(mtcars[1:5,], iris[1:5, ]) %>% map_df(~.x)