Apple yesterday released a firmware update designed for the MagSafe Battery Pack, and it turns out the new firmware enables 7.5W charging while on the go, up from the previous 5W limit.
In an support document, Apple says that MagSafe Battery Pack owners can update their firmware to the new 2.7.b.0 release to get the faster 7.5W charging capabilities.
Updating the MagSafe Battery Pack can be done by attaching it to an iPhone and waiting (a process that can take up to a week), or using a Mac or an iPad to update within five minutes. Apple suggests users attach a Lightning cable to a MagSafe Battery Pack and then plug in the USB side to an iPad or Mac to initiate the update process.
You can check to see which firmware version your MagSafe Battery Pack is running by attaching it to an iPhone and then going to Settings > General > About > MagSafe Battery Pack. You will need version 2.7.b.0 to get the 7.5W charging.
When the MagSafe Battery Pack was released in July 2021, many users were disappointed to find that it would charge at a maximum of 5W while on the go as other MagSafe accessories can charge at 15W. When plugged in to a Lightning cable, the MagSafe Battery Pack can charge at the full 15W, but that is not possible when it is used without a power source.
As of now, those who install the firmware update can charge their compatible iPhone 12 and iPhone 13 models at a faster 7.5W rate. It's still not as quick as the 15W MagSafe charging, but it is equivalent to the fastest available Qi charging speeds on the iPhone.
Source: Macrumors