Genesis puts the 12V battery in the boot on its saloons and on the GV80, under the floor panel beside the spare wheel well. That keeps it away from engine heat, which helps in Dubai, but it means the boot has to be emptied before work starts. The cars use AGM batteries from the factory. Swapping one for a conventional flooded battery is a false economy on a car with this much electronic equipment.
A battery sensor on the negative terminal tells the car how much charge is available. After a change, the sensor recalibrates on its own once the car has been left locked for a few hours, so start-stop and some comfort features may take a day to return. If the battery is completely flat, the electric boot release will not work. The technician feeds power through the jump terminal under the bonnet, opens the boot, and carries on from there.