iPhone 16 Pro Max battery damaged by power surge

If the power flickers or goes out while your iPhone is plugged in, it’s normal to worry, but modern smartphones and high-quality chargers have built-in protection systems. In the event of a severe power surge, the wall adapter is the one that "sacrifices" itself. At worst, the damage might reach the phone's internal power management chip (PMIC), but rarely the battery cell itself. If your phone won't charge at all after the blackout, gets unusually hot, or the battery percentage drops drastically in minutes, something might be damaged.

Try switching to a different cable and power adapter. If your phone charges normally and doesn't overheat, the safety features did their job and your iPhone is perfectly fine!

Extra tip: always use original or certified (MFi) chargers—they are the only ones that act as a proper shield against power surges.

A power spike would not damage any device unless the power source was of inferior quality (e.g., gas station/supermarket chargers). An inferior quality charger can also endanger you. 2 counterfeit iPhone adapter video

Is your phone working as usual since the outage? That would suggest that nothing was harmed.

No

Search for accessories that have completed MFi certification. Once an accessory has completed MFi certification requirements and is reported to Apple as sold/distributed, it will be searchable in our public database of authorized Lightning, headset, charging, iAP-enabled, and Find My network-enabled accessories.

Learn how to identify counterfeit or uncertified Lightning-based accessories.

You may try this (The suggestion is intended as a guide to help you find the right options and should not be interpreted as an endorsement or promotion of any product. Please conduct your own research and make an informed purchasing decision.) --> https://amzn.in/d/06mPoWvc