Eli5: What happens when you use a powerful charger on a smaller device?

Question

I plugged my phone into my laptop charger to see what would happen. My phone on 10% said “charge time 2 mins”. But then after a bit it changed to 45mins.

Does the phone somehow change the power of the charger to a more sensible power?

My phone has a fast charger which is usually “1hr” to fully charge.

In: 5

Answer 1

Most chargers have a controller to avoid over charging a battery.

They either send a digital signal to communicate with the device asking it what it is and the battery capacity or it is just sending some power in the beginning and checking the voltage and amperage this circuit sends back. And adapting to it.