F........9

I bought my Delta 2.0 last year.; No instructions on charging except a few Utube on line posts. When I plug this until in no lights illuminate is that correct? I have been able to charge it for a few months and since it turned 9 months old it seemed to not charge and it stays orange when I use it not green like when I first got it. Also could another vape cartridge be the problem? Not a Delta cartridge. Thank you in advance.