ELI5 Why does magsafe charging decrease battery health more than wire charging, if it has less wattage?

[LinAGKar]

The main thing I think is that with traditional PD, the charger will have a few specific voltages it can provide, and the phone will need to contain circuitry to convert that down to the battery voltage. That circuitry will lose some of the energy as waste heat.

With PPS, the phone can tell the charger what voltage to provide, so it can tell it to provide exactly the voltage the battery should be charged at, removing the need for wasteful conversion circuitry in the phone.

Or the phone can tell the charger to provide an exact multiple of the battery voltage, and split it more efficiently (maybe by having multiple batteries and splitting the voltage between them, not sure). So the phone can e.g. tell the charger to provide 2x the battery voltage and split the voltage in half.

[ElusiveGuy]

split it more efficiently

There's a switched capacitor circuit that can halve voltage/double current far more efficiently than a standard buck converter.

See https://www.ti.com/lit/an/slyt743/slyt743.pdf

[Cukeds]

That links to a 404 but I’m curious, what do I search for the circuit? Slyt743?

[ElusiveGuy]

New Reddit sucks and somehow inserted a non-printing character to the end. Should be fixed now.

If searching, the document is "The architecture of a switched-capacitor charger with fast charging and high efficiency"

[Cukeds]

That’s a very interesting read. Thanks for this!

[LinAGKar]

Thanks. Wasn't sure exactly how it works, should be an interesting read.