[bgamari]

Most (essentially all) personal electronic devices charge with a fixed supply voltage (often 5 volts) and will draw up to some current. The product of current and voltage is power. Since we have fixed voltage, the power rating of an adapter is really telling you how much current it is capable of sourcing. For instance, in the case of a 12 Watt 5V adapter, the supply is capable of providing up to 2.4 Amperes of current. That is to say, the supply only guarantees it can keep its output at 5V if the device draws less than 2.4A of current. If the device draws more the voltage may sag which may cause the charge process to terminate.

What this means for your question is this: all other things being equal, the power rating of the adapter makes no difference to the charging process. So long as the device does not draw more current than the adapter is capable of supplying the charge process will proceed at the same rate.

[pawn]

I want to be sure I understand you correctly, because I'm not too confident in this subject. You're stating that if my device is designed to run on lower than 2.4A, but I charge it using a 2.4A charger, it'll frequently charge and stop charging, then charge again? Does this mean also that I want to be careful to not use a beefy charger for my phone, rather than thinking "bigger is better"?

[davismwfl]

No, I don't think that is what was being communicated.

Basically, your device is designed to charge at a specific rate and it will draw only up to a specific amount of current (amps). Having a device that is capable of delivering more current doesn't mean your device will draw that current. A cell phone for example will have a varying charge rate, something that generally is between .5 amps and 1amp, with some devices capable of drawing 2 amps. But if you plug your phone into a 5 amp charger when the phones maximum rate of charge is 1amp, it will only draw 1 amp.

So in the end, bigger does not equal better, except to say that your highest charge rate should be equal to or less than the charging device, which helps keep heat to a minimum.

[bgamari]

Correct.