I cannot confirm any charging issues. You’ll have to know, that not only the charger, but also the quality of the cable does have an enormous impact on the charging current. The FP does try to increase the charging current until the voltage drops under a predefined threshold (I think that is not changeable). So when the cable does have a high resistance, the current will be lower.
Unfortunately, there is no easy way to measure this resistance (you may need to get an App which shows you the charging current?).
Since I’m studying electrical engineering, I did measurements with a lots of cables at a current of 2 A and the only thing I can say is: The shorter, the better. But there are exceptions to the rule, so my ~1,5m original Samsung cable is very good. And a lot of cheap (“Chinese crap”?) cables are bad.
For chargers, I did test my RavPower Powerbank (2,4A Output) and my “Anker 5 Port charger 40W”, they both work very well.
And hey, I think I read somewhere, that the best option would be buying a “5V/1A” charger. This is just nonsense. As I wrote, the phone chooses the current itself.
The phone sticks to a precise protocol (I do not know which one FP2 uses, maybe @joe can help?), so many cheap or old chargers do not work properly. Modern chargers do have several protocols, so you can charge your iPhone, iPad, MP3-Player and Android Phone with the same charger. (Anker calls this “PowerIQ”, EasyAcc says “Smart Ausgang”, which is German for “Smart Output”, RavPower says “iSmart” and these are just random picked examples)
Simply check, if the charger says “Android compatible” or anything like that.