Originally Posted by Teknikal
My opinion is anyone who thinks the wall charger makes it last longer is probably imagining it, the way I see it is it's 5 volts going in either way no matter where it comes from.
I will admit I have seen others say the same thing although it is also possible your pc's USB isn't quite up to supplying the voltage, wall charger is probably the best option as long as it isn't a cheap one but shouldn't really make a difference in how long the device lasts.
It isn't the voltage (which is, as you say, 5v), it's the CURRENT and the real difference is quality/speed of charge due to available current... USB sockets on computers supply a maximum of 500mA (and often less) whereas wall chargers normally range from 1,000 - 2,000 mA which means that the charge time is substantially reduced as well as never stopping (and discharging the device) by going to sleep... they give optimum charging cycles as battery is are designed to take fast (high current) charging to 80% and then drop back to trickle charging to finish. This probably does extend a single charge cycle if you read the manufacturer and inventor's specifications for Li-On and Li-polymer batteries and is certainly more efficient as well as taking less time to charge.