Therry Racon gave Charlton a 31st-minute lead and although Dale drew level in the 51st minute after Marcus Holness had headed home at the second attempt, Charlton struck twice more through Dean Parrett and Paul Benson.
Powell, whose side were held by Bristol Rovers on Saturday, said: "I'm very happy and our fans go home happy. It's an Easter we've got four points from, but actually I feel we should have six.
"I won't talk too much about the Bristol Rovers game when we were cruising, but we ran out worthy winners in the end.
"Obviously they put us under pressure. It's a tall ask and two games in 48 hours is tough. But I kept faith with the back four, freshened it up a little bit in midfield and up top and it worked for us, so I'm very pleased."
Source: PA
Source: PA