Originally Posted by xeno000
The armor was draining Tony's arc reactor in The Avengers simply because he had to call on it to do so much. He used every system and all of his armaments (lasers, etc.) to their max, and took a hellish beating on top of that. When he exploded a Leviathan from within he ended up with the armor shredded and drained of a lot of power. Then the Chitauri started in on him. That explains the power issues, at least to my satisfaction.
That's true of the comics Mandarin, but in the MCU he has spent years working behind the scenes to set Tony up for the kill. In all the time the Ten Rings has been working to destroy Stark, from that cave in Afghanistan to helping Vanko get at him in Monaco and onward, the Mandarin did not show himself at all. Obviously he is going to emerge from the shadows, but I wouldn't expect him to openly engage in battle with Tony until the very end of the movie.
But I thought his energy source is suppose to be massive and he didn't seemingly rush to change his chest piece after the battle was over.
I assumed his suit shut down because it was in space, but it didn't seem like it started up once he was back on the ground and awake. Yet it was working when they confronted Loki.