Download and install this: http/batterycare.net/en/download.html
Click detailed information and post here what the wear level is, as well as designed, total, and current capacity. Or just take a screenshot of the tool and post that here. It may be a bad battery.
Many laptops only allows the battery to charge up to a certain % like 50% - 80%. This is more or less to prolong the battery life when the laptop is plugged into an AC outlet. You would need to manually override the limitation (consult the manual) somewhere in the power options I think to allow the battery to be charged to 100%.
The theory is that the higher the charge the battery holds, there more likely lithium plating can occur. That basically means lithium particles will being to grow and combine together. When they do this they will no longer retain any electrical charge. Lithium plating occurs naturally over time; it cannot be stopped. But it can be minimized by not allowing the battery to reach anything near a full charge. The more lithium plating there are, the shorter the battery life.
If you mostly use your laptop at home then either allow the laptop to limit the battery charge or simply remove the battery if it is removable. When you want to you the laptop away from any A/C outlet for a long time, then at that point override the battery settings so that the battery can be charged to 100%.
I tried everything...from blowing the battery (which worked for my Toshiba), to removing the Microsoft ACPI from the device manager. I even changed the power settings. NOTHING WORKED. I was ready to buy a new battery, until I thought of an old school, nontraditional fix: I put the battery in the freezer. After an hour in the freezer, I reinstalled the battery into my VAIO laptop. It started charging again!