Which wall charger - 5V or 12.5V ?

[peedee]

Can any electronics expert advise on the best charger to use?

The wall charger that came with my 40GB colour iPod (which was supplied with the full kit of the dock, firewire & AV leads etc ) has a Firewire port in it and operates at 12.5V 0.4A (as printed on the charger itself). The wall charger that came with the newer 60GB iPod (no kit - no firewire lead) has a USB2 port which operates at 5V 1.0A.

Which, if either, is the most efficient charger?

[SDA]

Assuming that those ratings are accurate, they would charge your iPod at exactly the same rate. I'd use the Firewire one, though, because USB isn't very good for higher currents. Probably doesn't matter, though... just use what you have a free port for.

[airman]

From what I rememeber from chem... (and although I took it this year, its not that much) multiplying volts by amperes gives some sort of rate related number:

5 volts x 1 amp = 5 (???'s)
12.5 volts x .4 amps = 5 (???'s)

so they look exactly the same... but I could be be just making that up, thinking it's right...


-edit-

I googled it, and I was right

5 volts x 1 amp = 5 watts
12.5 volts x .4 amps = 5 watts

and watts is the signifigant number. since volts are the frequency and amps are the ... something else

wow I started to sound smart... then failed

[~tl]

Yep both adapters should be pretty much the same, because, as explained by airman, they both draw 5w.

TOM