How charging sources are prioritized for Macbook M1 Max?

MKV666 wrote:

Thank you,

In conclusion - when on heavy loads it's best to use the 140W charger because otherwise you will constantly discharge the battery or worst - lower your clock speed when the battery is drained.

Correct?

No. As long as the battery is working, it should be fully capable of operating at maximum performance. The battery is capable of providing considerably more power than the input power from a power adapter. The only reason why display brightness automatically dims when external power is removed is to improve battery life.

It’s rarely going to ever need even 140W. If it’s requiring that much power for more than just short peaks, it will either destroy itself or go into thermal shutdown.

It's rare for almost any notebook computer to draw more than the maximum input power. It can go higher for peaks (where it will draw from the battery) but that's not a big issue. If a MacBook Pro is continuously drawing 80W for minutes, there's something wrong where it could destroy itself in short order.

The batteries themselves are capable of providing far more power than their the input power, but again using that much power would be rare. If it could somehow operate like that without damage, the battery would be gone much faster than the 12-24 hours that Apple advertises. Likely less than an hour.

I don't believe that it accepts more than one power input at a time. You can pretty much find out which one is being used by checking the Power information in System Report.

Apple sys they want the device to use the "best" power source, but at this writing, it tends to be the First power source. Whether it will switch if the first is inadequate, we have no reports yet.

Standard USB cables only support up to 100W max, and some only 60W.

The 140 W number is for Fast charging, and is only available through MagSafe.

When a Mac needs more power than the external power source can supply under heavy loads, it freely 'borrows' power from the battery.

when operating normally and not under load, your mac can very slowly 'top-off' the battery. This might take as long as 24 hours to recharge from nearly empty back to nearly full, and if adequate power were available, it would ordinarily attempt a power cycle instead.

Rather that shutting down under heavy loads with too little power available (total from All sources) power management would slow the clock speeds and processing back to something sustainable.

Your Mac performs best when connected to the external powerr. When external power is not available, it may perform more slowly. When the external power is not enough, the battery will be used to make up the deficit. When the battery level falls too low, as usual, your mac will stop processing and hibernate to save power.

Chargers don't push power, devices draw power. So, if a device needs 50w it will draw 50W regardless of the rated wattage of the charger and a rated 96w charger will loaf along. If you use a 30W charger, the charger will likely overheat form not being able to meet demand as well as take longer.

The battery is charged, nothing else. While that's happening, each component draws what it needs or attempts to do so.

You can't transfer data through a port that's got a charger attached unless the charger is inline somehow with a data supplying device.

The battery supplies power and the amount of load will not ruin your battery. Simple usage uses up a battery and the heavier the load the faster that happens. Batteries also self discharge at some reduced rate. That's why a battery at 100% that's unused will still lose power gradually.

Your best bet is to ue the correct charger, charge it when necessary, use on battery when you want and let the battery and its circuitry handle the specifics of micromanagement.

The battery has a lot of capacity. You won't notice it is borrowing power from the battery unless you run it for a long time under really heavy loads. (or under battery power alone.)

The clock speed only gets lower when the battery power alone (or provided combination of battery power and external power) is not enough -OR- the computer is getting too hot.

When the battery gets low enough, your mac can not proceed, so it warns you, stops processing, and closes down until the battery can be replenished.