Battery life (not endurance) extender for windows?

I used to have a lenovo (it died in a tragic car accident) which had a function to stop charging the battery at 80%. This was supposed to be easier on the battery than charging to 100%. Does anyone know of a program to do this on any laptop? I've tried searching but can only find proprietary programs for Dell, Sony, Samsung, etc. and can't get any that will run on my laptop.

edit: Also if there's a way to stop the battery from charging manually I could automate it but I haven't been able to figure that out either. I tried disabling something along the lines of ACPI method battery or something like that but it just took the battery meter off the systray but it still charged.