Can I use a 61W USB-C Power Adapter with M1 Pro with 10-core CPU

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I have a MacBook Pro 13" with the 61W USB-C Power Adapter (of which I have several). I have ordered a MacBook Pro 14" (M1 Pro with 10-core CPU) which comes with a 96W USB-C Power Adapter.

Can I use my 61W USB-C Power Adapter to safely (will it overheat?) charge my new MacBook Pro 14", I appreciate charging will be slower? Also, will using a lower rated adapter impact on the battery?

Thanks in advance.

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Yes, can you safely use the 61W USB-C adapter to charge the MBP 14. I routinely use a 30W MacBook Air charger when I am outside. (I also tried the 20W iPad Pro charger for chuckles, and it actually works!) When I am at my desk, the Mac is powered by the CalDigit Element hub at 60W.

The Mac will draw as much power as it needs, and the charger will supply as much power as it can (up to the maximum rating). If the charger cannot supply enough power, then the battery will slowly drain (which happens to my 16" i9 under max load, but yet to see under the M1 Max).

According to various sources (Anandtech, NotebookCheck), the CPU uses around 30W at full load. The GPU can draw quite a bit more under full load.

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Thanks for this, and I assume I can charge through the USB-C port.

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Yes, you can charge the MBP using any of the three TB4/USB-C ports. If you plug in the 96W adapter into the USB-C you can also fast-charge the 14".

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Just to add to @chengengaun’s excellent summary, no your battery won’t age faster because you charge it at lower power. In fact, quite the opposite. These types of Li polymer batteries age most while they are fast-charged, i.e. charged at high power up to ~80% of their capacity (circuitry prevents charging at high power all the way to prevent hazardous overcharge). Charging them slowly, which you are effectively achieving by using a lower wattage power supply, is actually the most gentle way to charge them.

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Glad to hear that Apple’s power supplies have functional current-limiting circuitry.

I’ve seen power supplies overheat and die when overloaded, but these have always been cheap no-name units, not good quality ones from major brands like Apple.

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It is indeed good practice to stick to quality chargers, cables and peripherals - the temptation is great to use a small-yet-high-powered charger, but I have came across anecdotal accounts of PCs/Macs shorted when using cheap chargers. (I am also particularly wary of using thumb drives from unknown manufacturers e.g. those given at trade shows.) Makes no sense to damage thousands of dollars worth of equipment over a cheaply made accessory.

At the other end of the spectrum, I also tried to use the 96W charger to charge my iPhone. It works - but makes no sense (other than lazy to find a smaller charger when the 96W was in front of me)…

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I sometimes do that too simply because I only brought along one charger with my MBP. I got myself one of these so I don’t even need a 2nd cable when traveling really light.

https://www.amazon.com/Female-Converter-AirPods-9V2A18W30W-eMarker/dp/B0927R5PB3/

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Just want to add something: Apple must have discontinued the 61Watt USB-C power-adapter. I was looking to get a spare one for a user, when I couldn’t find it on the Apple site. Looks like its now replaced with a 67watt USB-C version. Which is fine.
I knew you could use a higher wattage charger with compatible models (Magsafe…). Same applies with these USB-C versions.