Battery. I used to keep my computer in my car for use on the road. I recently tried to use it and

Question

I used to keep my computer in my car for use on the road. I recently tried to use it and it will not rub off the battery. The power usage shows the battery at 73% and charging. The computer is less than two years old and has been operated on house power most of the time. Is their any simple way to test the battery or do the connections fail?