Apple Watch Series 7 has a fast charging system that Apple claims is 33% and can charge the watch up to 80 percent in just 45 minutes. You will need to use the Series 7 charger, which is a new Apple Watch Magnetic Fast Charging Charger. It's faster than the older model and offers similar charging speeds.
Although the old and new USB-C chargers look identical from the outside (assuming that you have a USB charger that can output the correct wattage), only the new cable can fully charge the Series 7 (assuming that your USB-C charging device can supply the right wattage).
You must use the Series 7 cable.
Apple has stopped selling the USB-C charger without fast charging. However, they are still available at Amazon and other retailers. This means that you will not be able charge your Apple Watch using an existing charging dock or stand with a built-in charger.
This doesn't apply if you have an older Apple Watch. Even if you use the correct fast charging cable, fast charging technology requires a Series 7 Apple Watch to work. Apple's website states that fast charging is only compatible for Apple Watch Series 7. Other models will require regular charging.
