Question about USB-C Power Adapter wattages for iPhones vs. MacBooks?

To put it very simply, the rating on the charging device label is its maximum power output capability. Strictly speaking an Apple charger is simply a power source, and the real charger and control are within the device being charged. The device will decide how much power it should take and how fast it should charge, up to the limit of the supply’s rating. That means you can use a high rated Apple charger without problems if the device being charged has a lower demand.

Using a lower powered charger on a power-hungry device is less predictable, it will either max out the charger and take longer than expected to charge, or the device may detect the inadequate supply and not charge the battery. This is often seen on laptops, where a low rated supply might be able to run the processor but there is not enough left to charge the battery while the device is in use.

Watt == Volt * Amps

volt is a level 5volt is 5volt if you connect a 24volt charger you kill the device

amps is a measurement of how many amps of current you can draw from the charger before it has to begin lowering the volts

so if your charger is a 1000Watt charger with 5volts you can safely charge your iphone with it, the iphone will draw the amount of current it's charging system was build to charge with , and the ability for the charger to provide more would be untapped

so you can't harm any of the devices using any of the chargers, but some of the more current hungry charging devices would charge very slowly but a low watt charger.