There is no harm to your iPhone by doing this, but simply put, you will be waiting significantly longer for your phone to reach 100%. With a 5-watt charger, it can take an iPhone 16 up to 4 hours ...
It’s important to consider the amount of wattage a charger will provide to your device. For years, Apple supplied “good-enough” 5-watt chargers in the iPhone box, which take about 2.5 hours ...
It will take about another hour and a half to reach 100%. If you don’t have 30-watt chargers available, you can achieve very similar results using a 20-watt charger. A 20-watt charger will ...