cam is charging very slow taken 3 days and only at 86%
Try turning camera off when charging might be quicker also check the usb charging point make sure it’s correct outage 
What is the charging source, e.g. mains, hub, PC, Homebase etc? Also, the USB cable used and the length of it will make a difference. I’m currently using an Anker mains fast charger and a fast charge rated 3A USB 1m cable, charge times are fine here.