Contents:

The battery is in the trunk under the compartment cover.
When replacing the battery, disconnect the negative (-) cable (1) and remove the positive (+) battery fuse box (2).
Remove the battery mounting bracket (3).
WARNING - Touching metal surfaces in the trunk under the compartment cover

Do not touch metal surfaces in the trunk under the compartment cover while the engine is operating or hot. Doing so could result in serious personal injury. Turn the engine off and wait until it cools down or wear gloves to replace the battery from the luggage room.
Your vehicle has a maintenance-free, calcium-based battery.
When recharging the battery, observe the following precautions:
Reset items
Items should be reset after the battery has been discharged or the battery has been disconnected.
Kia Stinger (CK) 2018-2023 Owner's Manual: Fuse/relay panel description
■ Driver’s side fuse panel ■ Engine compartment fuse panel ■ Rear fuse box panel ■ Battery box fuse panel Inside the fuse/relay panel covers, you can find the fuse/relay label describing fuse/relay name and capacity. ✽ NOTICE Not all fuse panel descriptions in this manual may be applicable to your vehicle. It is accurate at the time of printing.Components and components location Components Location 1. Roller assembly Repair procedures Replacement Put on gloves to protect your hands. • Use a plastic panel removal tool to remove interior trim pieces without marring the surface.