Power rating for iPhone 6s charger ?

Tablet chargers, including iPad chargers tend to have a higher voltage than that of phones. This is because tablets require more battery. The iPad charger will be faster to charge your phone. This only refers to the power brick (figure 1), not the power cable (figure 2).

Figure 1

Figure 2

h4ndcrafted wrote:

My ipad Air has a charger (American) that rates 12w on the side.

My iphone 6s charger (British) has info that is too tiny to read, but even so still doesn't say.

Is the iPad one more powerful and will it charge my iPhone 6s faster or vice versa ?

The first response is partly right, but for the wrong reason. Every USB adapter ever made has the same voltage output: 5 Volts +-0.5 volts. The important value is the CURRENT (amperes or amps) that the adapter can supply. Any device will only use the amperage it needs, regardless of what is available.

The short answer is the 12 watt adapter (which can supply 2.2 amps) will charge an iPhone 6 or later slightly faster than the adapter that comes with the phone, which can only supply 1 amp. But even though the adapter can supply 2.2 amps, the charging circuit in the iPhone 6 will only use 1.6 amps. So it won't be twice as fast. For all iPhones prior to the 6 there was no benefit to using a higher power adapter, because the phone would only draw 1 amp regardless of what the adapter could supply.

There's another factor at work; the phone will fast charge to about 60%, then slow down the charging rate to avoid any possibility of overcharging. Most of the charge time is going from 60% to 100%. If you watch closely, starting at zero the phone will reach 60% in about 40 minutes with the 12w adapter, and about an hour with the 5w adapter. But the time to full charge will be another 2 hours. The higher current charger is only a benefit in the initial charging, not from 60% to 100%. So overall you save about 20 minutes with the 12w adapter.