Is your home charger working properly and charges normally. If yes I would try another car charger. Both pieces if it’s a usb type. Sometimes the car itself does not allow the charger to function properly. See if you can charge from a different car.
If no then you might have a problem with either the battery, port connector, or the board. Are you using the same cable that you are using in the car? If so that might be defective.
Let me know so I can give you more suggestions