Cheap charger effect?

I foolishly went and bought a cheap charger for my iPod touch. What are the consequences? I am quite sure it will not short-circuit, but other than that what might happen? What happens if the circuit or voltage is too high? I would appreciate answers that include the technical side of this as I can't find that information. Does the authentic charger include a timer? I know Apple doesn't release this information but there must be another way of finding out. Or is it the circuit in the iPod that prevents overcharging? Or is it the combination or some message sent by the iPod to the charger? My mother won't be too happy about me buying the authentic charger after getting the cheap one. How will it affect the battery? And can Apple find out if I apply for a warranty after some other problem occurs? Thanks.

(I am not a native English speaker)

 

Thanks for the prompt reply. The exact same thing happens for me. For me, the high current or whatever also messes up the capacitive touch screen and makes it interpret any finger touches as some other gesture unless I hold the metal back with my bare hand to ground the circuit. However, I would like to know technically how the charger effects the battery and whether all the important circuitry to prevent overcharging is in the iPod or the charger. And what the effect is on the battery, whether it will reduce its lifespan or not.

 

Thank you for that useful information. I really appreciate it.

 

The Apple authorised reseller at my place said that Apple can know if we use unauthorised chargers and refuse warranty. Is that true? Thanks!