Other mistake: When Iron Man and Iron Monger are fighting, Iron Man catches the SUV, and you can see the family inside the car. Although the car is completely vertical, the hair of the people in the car seems to defy gravity.
Other mistake: When Tony's convoy in Afghanistan was ambushed at the beginning of the movie, he was riding in a non-armored HMMWV (Humvee). Prior to 2007, all vehicles that leave the bases in Iraq and Afghanistan are up-armored; under no circumstances would you be allowed to leave a base in a soft vehicle. The Airmen were wearing the Airman Battle Uniform, which was released for use in the Middle East around 2007, so the movie couldn't have taken place before that time period. Some people may try to correct this by claiming that the military doesn't have enough up-armored vehicles to go around, and they just got the short end of the stick. That is not the case today like it was a few years ago. Even if it were the case, the military wouldn't put a passenger who would be considered a "high-value target" to the enemy like Tony at risk for capture or death in a soft vehicle, especially with his knowledge of weapon systems that can be used against the U.S. if he were captured.
Chosen answer: It was basically a prototype made from, to quote Stane, "a box of scraps." It was not strong enough to last, especially when it came to powering Tony's high tech armor armor upgrades.
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