What brand is your third party charger? Is it a name brand or an off-brand?
While you cannot go wrong by sticking with Apple branded accessories, as previously suggested, there are reliable third parties and then there's everyone else. In the past with the 30 Pin dock connector, I've never had any problems with either Belkin or DLO chargers, and I currently use a Belkin Lightning charger in my car with no problems (so far, anyway, I've only had the iPhone 5 for about a month). (The Belkin charger was the only one available at the VZW store and Apple does not appear to make car chargers themselves.)
I would surmise further that if the accessory in question is available via the online Apple Store, then it meets Apple's specs and should be usable.