I have a dell G5 5587 not even year old since I bought it and having the same issue; IT DOES NOT CHARGE the battery, I even updated the bios and bought a new battery as my old battery got to zero charge then the system will not read the original battery at all; now my new battery is reducing charge 1% a week about, when I have to move the computer from the charge it reduce the charge, battery came with 47% charge. I called DELL for help, sends me to out of warranty department, I am so frustrated, I am very technical and I AM sure it's a manufacturer default. I NEED HELP PLEASE HELP.

Google for Dell's battery, charger troubleshooting guide. 

It will take you step by step.