You have several bottlenecks in the chain. The phones won't draw more than what their internal power distribution system was laid out for. If it requires a battery internally to run stable you can't just fix that by theoretically supplying more at another point. Batteries are very convenient because they can act as a buffer that is able to supply a high peak current. Modern CPUs and GPUs need a high peak current if you don't take countermeasures. Supplying that peak current from an external power supply would be quite expensive.
To rephrase your question:
Could we build a new phone that runs off a 80..120 W charger without battery? Absolutely yes.
Will it help older phones that were not designed to use such a charger? No, most likely that charger will change nothing.
Those aren't the problem. It's that you can't control what the user will do/use (a sort of unbounded problem). The 0.5w or the ultra ultra cheap chargers that let AC signal through or maybe it's not giving true/clean 5/10/20v.
Now you have to have an extra decision circuit that judges whether or not the wall is "good enough to boot the phone" and then ask if it's good enough to run it as well. Last thing you want is wall power to dip randomly and you can't switch fast enough and simply shutting off.
I understand why you would pick the battery as the requirement. You know the exact behavior of when the phone is safely bootable vs not w/ a predictable DC signal.
Yes, commonly referred to as a “battery emulator” in EE labs for mobile devices. Some are lab grade test equipment from big name vendors, and some are home-grown concoctions which use a power supply, capacitors, and adjustable load to shunt the power when the device tries to “charge” the battery. If a battery charging circuit is running, it’s generally not enough to just provide a DC power supply, it actually needs to be able to both source and sink current. But if the battery charger can be disabled, then a high current power supply, lots of capacitors, and a good short connection can be enough to replace a battery for a phone/tablet.
Sure, it must be possible. You just need to give the right voltage to the +/- pins, and most phone batteries have at least one or two additional pins which you'll have to reverse engineer. Usually a thermistor for temperature reporting, which you'd replace with a fixed resistor / voltage divider to report a constant temperature.
Apparently some manufacturers put the phone's NFC coil inside the battery instead of on the phone's back housing, so there could be a fourth pin for that. Or perhaps the battery contains its own microprocessor that answers a DRM challenge from the phone specifically for the purpose of blocking out third party battery manufacturers. Etc. etc.
Still there is the problem that the phone might have peak power usage above what its charger can provide, so you'd have to use a wall adapter with a higher amperage rating.
> Or perhaps the battery contains its own microprocessor that answers a DRM challenge from the phone specifically for the purpose of blocking out third party battery manufacturers.
Ah yes, good old anticompetitive practices. Sleep well, FTC.
This sort of thing exists! I use something like that with my DSLR for a webcam. It’s great, there’s no real battery involved, it’s just a power cable with the end shaped like a battery.
That should be sufficient. The most peaky loads are RF transmit, can be 10-20W instantaneous. If you add that with GPU operations and backlight, camera, etc. But I don't think it'd easily go over a few tens of watts.
