htop's smallest interval counts in 100ths of a second, had me confused for a bit. browserd using 6 hours of cpu time isn't unusual if you're using it and leaving it in the background. If you hit another power draw like that, take note if the device feels warm and grab the times like you just did. Also note if a page you visited happened to have Flash on it, since that seems to be when the browser behaves the worst for me.