Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
My girlfriend uses my old firewire power brick to keep her iPhone charged at her office. Using the power brick it charges up the iPhone just fine. She's never tried with the firewire plugged in to a computer's firewire port, although I wouldn't expect that to be any different.
 
I have been wondering the same, it appears that some people are saying that the new iPhone/iPod USB adaptors are only 5V whereas the old firewire ones are 10/12V

i have also read a forum saying someone tryed to use the iphone with firewire, and it caused the phone to overheat and DIE!!!

but i am very keen to do this my self with the old firewire/usb cable, so i can sync with USB and charge with firewire (no swapping arround cables)

hope this helps~
 
The spec on FireWire allows for the voltage pins to operate at up to 30 V DC. However the Dock connector for iPods and the iPhone utilizes separate pins for USB and FireWire power. If Apple did not want the iPhone to charge via FireWire it would have been a simple matter of disconnecting the FireWire power pins at the Dock connector and it simply wouldn't charge. However since the pins must be there and connected to something to charge the iPhone, they would have to assume and design for the possibility of receiving 30 V DC on those pins. If they did not then they were very poor engineers.

I have heard some rumors of people frying their iPhones via the FireWire charging but based on the frequency I've heard those versus the frequency I've heard "it works fine" I would guess that the fried phones are just typical component failure issues, not a design flaw.
 
Since I got it on launch day, my iPhone sits in it's dock most of the work day, 5 days a week with the line out going to some speakers and the firewire power brick plugged into the dock connector port to keep the phone charged. I've not had a single problem. Battery life has not deteriorated and the phone has yet to explode causing a ball of firey destruction.
 
FIRE WIRE KILLED MY IPHONE ! :mad:

i left it on the firewire WALL OUTLET charger overnight.
next morning... H O T ...and wouldnt turn on.

:apple:toast !

bring it to the Apple store... guy tells me my warranty is void because of some light scratches due to a drop day 2 b4 i got my case !

im going to hopefully run into some apple store reps at a bar i know they hit up on wednesdays, tonight. If that doesnt work im bringing my girlfriend with me back to the apple stare to demand action...
she knows how to demand action, trust me.

-andy
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.