@SlicerDicer @sun so it's totally possible but the chance of failure if you didn't put the back on properly or damaged the gasket is the big risk

honestly the battery on iphones should be in a compartment with a door or something so you can pop it open (maybe a screw holding it closed?) and slide the battery out. This would of course require they move away from the soft batteries but they're already doing that for the new Pro models