A point was good enough to secure Cardiff's promotion to the top-flight, but Powell was also pleased with his players who produced a determined display against the Championship leaders.
Cardiff's David Marshall had to pull off two fine saves to preserve the draw as he pushed Johnnie Jackson's first-half free-kick onto the post before pulling off a stunning stop to deny Ricardo Fuller his second goal in four days.
Charlton are sitting comfortably in mid-table and they stretched their unbeaten run to five games.
"We had good spells," said Addicks boss Powell.
"I said to the players we had our moments, we definitely played our part. It keeps our unbeaten run going and it is another clean sheet.
"My players played some good stuff at times in a hostile atmosphere.
"We showed a lot of character and we've taken four points off Cardiff so we are not that far off. I am very pleased with the display."