Could easily be out of spec chargers. There are a number of prominent iPhone repair specialists (Louis Rossman, iPadRehab and such) that highly recommend against using 3rd party USB power supplies because there’s no guarantee of quality.
You can easily destroy your expensive device. They even recommend against using the built-in USB ports in planes and transit and instead using an AC power port with your OEM charging adapter to be safe.
Could easily be out of spec chargers. There are a number of prominent iPhone repair specialists (Louis Rossman, iPadRehab and such) that highly recommend against using 3rd party USB power supplies because there’s no guarantee of quality.
You can easily destroy your expensive device. They even recommend against using the built-in USB ports in planes and transit and instead using an AC power port with your OEM charging adapter to be safe.