Lenovo P/Y/Z Series :: How To Set Z580 Battery Settings To Fully Charge

I bought a new Lenovo Z580 this past June. Shortly after I began using it, a system message popped up explaining to me that since I often have my laptop plugged in, it would conserve battery life if I let the system change my settings so that the battery didn't fully charge -- this would save battery life over the longterm and I would be free to change the setting whenever I wanted to. Well, this has been the biggest mistake ever. I now essentially have a desktop because I cannot find any setting that allows me to change the battery to fully charge (it only charges to 40 or 50%). There isn't any mention of this feature in the user guide materials that I can find and none of the Power Options allow me to change the battery charge capacity.