What applications should I avoid charging my iPhone with?
You can charge an iPhone with any reputable USB charger, but unless it is designed for Apple will charge very slowly (~100mA the USB default).

In some cases (this is based on earlier iPod dock) the device will refuse to charge if it incapable of negotiating a charge rate.

You would have more luck plugging into a computer. This will still be slow, but should be capable of negotiating a 500mA rate).