I have a 2023 16" MacBook Pro (M2 Pro). I'm trying to determine some levels of minimum charging requirements.

It's well advertised that to Fast Charge, you need the 140W charger and to use the MagSafe port. It's also well advertised that you can charge (not "Fast Charge") with the Thunderbolt ports, as per older models.

What I'm looking to understand is some level of minimum wattage necessary for, say, very slow charging. Or just maintaining current battery level. I understand this can vary under heavy usage, so there may not be a fixed answer. I wouldn't concern myself with that, except that sometimes poorly behaved apps will generate a heavy load when the user isn't doing anything special.

Would you expect an older 96W charger to be sufficient, for example? What about something even less powerful?