When you use an old charger on a new phone, there are a few things that may happen. Firstly, it is important to note that newer phones are designed to be compatible with a range of chargers, including older ones. This is because manufacturers understand that people may have older chargers lying around and they want to ensure that their phones can still be charged using these older accessories.
However, there may be some differences in voltage between the old charger and the new phone. Older chargers typically have lower voltage outputs compared to newer ones. This is because older phones often required less power to charge compared to the advanced technology we see in newer smartphones.
But the good news is that newer phones are designed to handle different voltages. When you connect a new phone to an old charger, the phone will detect the lower voltage and adjust accordingly. It will take only the amount of power it requires to charge effectively, without causing any harm to the phone or its battery.
In my personal experience, I have used older chargers with my new phones on numerous occasions. I have found that the phone recognizes the lower voltage and adjusts accordingly. I have never encountered any issues or damage to the phone or its battery as a result of using an old charger.
It is worth noting that while the phone will adjust its charging to match the lower voltage, it may take slightly longer to charge compared to using the recommended charger. This is because the older charger may not provide the same high-speed charging capabilities as the charger specifically designed for the new phone.
To summarize, when you use an old charger on a new phone, the phone will recognize the lower voltage and adjust its charging accordingly. The phone and its battery will not be harmed in any way. However, it is important to keep in mind that using the recommended charger will provide the fastest and most efficient charging experience for your new phone.