Did you know that you can discharge a smartphone so deeply, that it won't take a charge again, from any charger?
Or actually, almost any lightning or usb-c powered/charged device... Because they don't support completely dumb charging at all.
In order for a usb-c or lightning port to actually allow power to flow, there has to either be two way communication between the charger and the device, or the port controller has to at least detect that the cable is good, and doesn't have too much or too little resistance or impedance (meaning no dead loads or dead shorts). The port literally won't accept power, and the charger won't send it.
This is a safety measure, because USB-C and lightning, are both omnidirectional and water resistant ports. So the port and charger both try to make sure they arent going to short out, or cause a fire etc... before they let all but the tiniest test current flow.
Anyway... its possible to drain a battery enough, that when you plug in the usb-c or lightning cable, either the port controller just won't work period; or the battery or safety circuit can attempt to draw too much power from the port at startup, such that the communication is disrupted, or the port goes into safety shutdown.
Now, it's certainly possible for the designers to design around that... They just don't bother usually.
This means that if your phone dies completely, to the point where it won't light up at all, or register a button press at all etc... Then you leave it in that state for days or weeks... When you next plug it in, it may not take a charge at all, even on a theoretically completely dumb charger.
Now... Sometimes you can bring a device back from that state, by just plugging it in to a higher powered dumb charger (or a more intelligent smart charger) that supports your phones supported charging voltages and amperage (some phones can now draw as much as 28w in superlatives charge mode, but most top out at between 7w and 15w) making sure it doesn't get too hot when you do, and then let it sit for a while (as in hours and hours... overnight etc...).... But sometimes, it just won't work, period.
As it happens, my girlfriend, and one of my other housemates, have done this to multiple devices... They tend to run devices down to almost shutting odd before charging, and they also tend to lose devices for days at a time... Which in combination, tends to induce that "won't charge no matter what" state.
There is however, a workaround...
This little thing, is a USB testing device. It can measure electrical characteristics of a USB port, cable, or charger, in real-time.
I have several of this type of device, and I usually use them to test USB ports, chargers, cables, and devices, for their charging ability, power delivery ability etc... No new USB device gets plugged into anything I care about, without my checking it out on one of these testers first. Because USB kill devices exist, and because bad USB devices can kill a computer or a charger, right quick.
This one... an AVHzY CT-3 ($66 plus shipping from the company store, or about $70 prime at amazon) also has some neat additional functions, like 10,000 point data logging, external load testing, output of all measured parameters to your PC, an oscilloscope on the USB power lines; and critically, full protocol control and triggering for every common charging mode from every common vendor.
Which means you can plug it in to a high powered charger (I've got it plugged into a 100w MacBook charger right now), plug the output into a dead phone, go into triggering mode, and force a charge down the line without doing a safety shutoff or allowing communications to be disrupted and stop the charge etc...
Using this trick I have been able to resurrect two phones that were otherwise dead, in just the last few hours. And now, I can use them as spare phones, or do things like, convert them into media streaming devices, or remote monitored cameras and microphones... or trade them in on a new device and get as much as $200 credit... just off the top of my head.
