You can power on the charger before connecting the discharge wires and balance cables. But I always mention to power charger on last to prevent any mistakes. Not sure why he mentions it must be on because it doesn't have to be on. I don't see any benefit. The main benefit of powering everything on after is when I plug in my iCharger 208B it will read the pack and tell me the Lipo Cell. If I do it the other way and power on charger first - I'll have to mainly change my pack to 4S or 5S depending on what it is. I'm not sure on the correct method but I find that powering after I plug in is more then adequate, safer and easier.