Still, there are better armour choices out there. Look at some values for titanium or Lexan.

Also, running out that amount of kJ on the disc you will incapacitate yourself when your disc comes into contact with another bot. Id estimate that your disc would put out about 30-40kJ. Dont take those values, though, theyre just examples. Try and calculate it, or dont put a kJ value up at all if you cant figure it out.