Junker87: So what exactly is it ?? once or twice a week!!

Depends on the phone and how you use it.

Yes, POET should have really said soething like "Our technology saves you between 50 and 88 percent of your smartphone's processors' power consumption, depending on the usage pattern you impose on the RF chip and on the GPS receiver, depending on which apps you are executing and how long, etc. However, please take into account that your smartphone's display's power consumption does not necessarily correlate (positively or negatively) with your smartphone's processors' power consumption. Now would you please go and calculate for yourself how often you would have to charge your phone when using our technology!"

However, the speaker they had engaged was unable to squeeze all this into the given 15 seconds timeframe and unfortunately Peter Copetti was unavailable on that day. So they resorted to "charging your phone only twice a week."

(And for those who didn't notice it already, this was irony (except for the first sentence).)