I travel, and have a competent 100w GaN charger that works for all my other stuff.
my new laptop has the big new 140 watt charger, but I’d rather travel with what I’ve got. Do I NEED the 140 watts to charge my new 2021 MacBook 16”?
No. That should be fine unless you have some unusual use. The original one might charge faster until the charging rate inevitably decreases as it gets closer to full. But that's normal with any well made lithium-ion charging system since that's to control heat and reduce battery degradation. If you have enough time to charge it, you should be fine. And you should expect that it will charge while using unless you're running something using up an inordinate amount of power.
2021 MacBook Pro 16” charge with a 100 watt GaN charger?
