Probably you are reading the NC file with VNL? That gives just a few decimals, if any, yes.
You can use a small script instead. Let's fist imagine we have only one NC file (I know, you have many, but let's take it step by step :) ). We can then read the total energy from the NC file, and print it, using a few lines of code
total_energy = nlread("file.nc",TotalEnergy)[0]
print "%.10f" % float(total_energy.evaluate())
This prints the total energy with a lot of decimals!
Now, what to do if we have more than one file? Python to the rescue - specifically the module "glob"! Assuming we want all the NC files in the current directory:
import glob
list_of_files = glob.glob("*.nc")
for file in list_of_files:
total_energy = nlread(file,TotalEnergy)[0]
print "%s\t%.10f" % (file,float(total_energy.evaluate()))
If you just want some files, just create a suitable file mask instead of "*.nc", like if your files are "abc_2.1.nc", "abc_2.2.nc", "abc_2.3.nc", and so on, use "abc*.nc".
Have fun!