https://wccftech.com/2020-iphone-se-5w-vs-18w-charging-speed-tests/

Apple’s newest 2020 iPhone SE is practically the iPhone 8 with minor changes on the inside. What’s not changed, unfortunately, is that small 1821mAh battery present inside that 4.7-inch display. Also, Apple didn’t do its customers any favors by bundling a 5W power brick as part of its accessories, so if you want faster charging speeds, you can pick up Apple’s 18W adapter separately. However, what will be the benefits of upgrading from a 5W adapter to an 18W one? These tests will provide all the data you’re looking for.

According to charging tests done by PhoneArena, using a 5W charger, it takes around 2 hours and 30 minutes to charge that small 1821mAh cell. Sadly, what’s disappointing for users is that you won’t see any fast-charging benefits using this power brick. During extensive testing, a 30-minute top-up only resulting in around 28 percent of charge.