Chosen Solution
My new macbook is taking too long to charge (taking about 18-20 hours to charge fully). The cycle counts for this macbook are just 4. Moreover, this macbook is new although but I have started using it after few months. Furthermore, I have even tried resetting SMC. But still facing this issue. Besides that, I have also installed coconutBattery.
You’ll need to try a second charger & USB-C cable to be sure, I’m suspecting the charger has a problem. I would visit an Apple Store or Apple dealer to see what their charger does. Clearly the 7.7 Watts is low. You might want to invest in a USB-C power meter Type-C USB Power Meter
