I'm not expert in this field, so i trust what you say. Anyway i still prefer the "plug" method because is not so invasive and because i'm not good at soldering, never soldered anything in my life, and don't want to learn on my preferred phone

Again, i'm not an expert in the field of chemistry and physics, i simple used wikipedia to found the resistivity of that material: http://en.wikipedia.org/wiki/Resistivity
In the chapter 2 there's a list of material, i compared the Tin with the Copper, and seems that the Copper has much lower resistivity than Tin (soldering wire): 1.68×10^-8 vs 1.09×10^-7 ohm metre. I take this information as is, i don't have an idea how this behavior will apply in our real case, real misuration etc, i used the simple principle low resistivity = better

Probabily, considered how short are the plug cable, you are right in saying that there's no real world difference.

Thanks to you for the interesting answers

Thanks, i've installed it, seems simple but it should do the trick. Anyway i still prefer the terminal when i can

In the second charge cycle i've reached 95%, but watching the Battery Graph i've noticed that also in the first cycle i've reach that point, but once the phone was charged, seems that it begin to discharge even if plugged. So, when i unplugged the phone it was discharging from six hours, this explain why it was at 80%. This behaviour is normal?

So, considering this, yesterday the phone last from 2.30 a.m. (when the phone begin to discharge when unplugged) to 9 p.m. around 19 hours, with
1) 3G connection always on with mail check every 30 minutes
2) 120 minutes of skype/gtalk online
3) 90 minutes of bluetooth on with headphone connected
4) 45 minutes of web browsing
5) 30 minutes of phone talk.
6) 40 minutes of gpodder audio streaming
7) 60 minutes with pedometer widget on (used during my daily jogging)

What do you think about this duration?

EDIT: I'm getting confused. Today i charged the phone through USB, after 2 hrs the QBW indicate 90 perc, then in the next 2 hrs it go to 95, with charging led still active. I unplugged the charge, made 20 mins of phone call and the perc go down to 75.

So i disassembled the two battery and put one at time to see the charge. One was at 75 the other at 50, this should not possible if they are connected. So seems that the phone was using only one battery, but this not explain the longer charge period.

Anyway i remade the connection with soldering wire that is more flexible and adaptable, switch on the phone and the charge say 65, that is the average of the two charge that i've detected. So i will test until for two days to see if it work.