Is there a risk using the Apple charging bricks from my 15" MBP on a 13" MBP? have been doing this off and on with my 13" 2019 MacBook Pro. I have been having significant charging issues with this machine. It will be plugged in, but not charging. I now have a new 2020 13" MBP and I’m wondering if I need to not use this 15" charger. Did I break it, or is this just a fluke with this old 2019 machine?
It’s okay to use higher wattage adapters.
Here’s an article from Apple.
That’s what I thought. But I have been having intermittent charging issues with this 2019 13" MBP since it was about a month old. I knew I should have taken it in for repair, but I couldn’t be without it for work. I just don’t want to mess anything up with this new machine!!!
The 2020 MBP with the updated Keyboard is sitting here taunting me to take off the plastic!
I’ve been using the Apple charger and an Anker USB C - USB C cable. Surely that’s not the problem, is it? Apple cables still suck!
You could always switch to the Apple cable and see if the issue changes.
The easy way I like to explain this is that volts are pushed, amps are drawn. This is true for all chargers.
So voltage has to be the same, or you’ll blow something out - but the device will only take the amperage that it needs.
One of the many reasons I throw away the dedicated micro USB headset chargers when I’m sorting through my cable bin - pretty much any charger will work, and those chargers won’t charge anything but a headset. 
With Apple’s power adapters, things are a bit more complex. Voltage varies with the wattage of the adapter, there’s a whole handshaking protocol between laptop and adapter, etc.
This description is about MagSafe, but I’m sure usb-c is equally involved.
All of this is necessary, of course, because lithium ion batteries can explode if mistreated. Therefore manufacturers go to great lengths to ensure that doesn’t happen.
That’s surreal. I guess I get to amend my comment to “this is true of all ‘dumb’ chargers”. 
I would think that USB-C would have to work on some sort of standard (looks like maybe a few standard voltages, with auto-negotiation like you describe?) though, otherwise all the third-party USB-C chargers wouldn’t be universally compatible.
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With the old Mac 2019 MBP I have charging issues regardless, even with the apple cable. I just want to make sure I don’t mess up my 2020 MBP