Chirping sound from USB Charger

[amujee]

Last night, I flashed my rooted stock froyo d2 with the leaked gingerbread rom and it works great, like having a new phone. But today I noticed a chirping sound coming from my charger when the phone was charging. I thought it might be faulty but I tried my friends Droid 1 and it charges normally. Also, I never noticed the chirping when I had froyo on my d2. I'm using the Belkin Micro USB Charger with the Motorola usb cable. Has anyone else experienced this?

 

[amujee]

Update

I guess no one else has had this problem.

I think I may have figured it out. I forgot to mention that I was using an official Motorola extended battery. I also forgot to mention that the charger was hot when I unplugged it. But today, I went back to using the regular battery and the charger behaved normally.