Is there any tool (for Windows 7) to set a threshold for when the laptop battery should stop charging? I could use the Lenovo Power Manager, however I actually prefer Windows' native power management for the other tasks.
Windows – Keep the battery from charging fully (without Lenovo power manager)
If I understand your question, you are trying to keep your battery at a level lower than 100% (let's say 40%). I wanted the same thing in the past because I used my laptop mainly as a desktop, and keeping the battery at 100% all the time was not necessary and not healthy for it. What I found is that even though in theory it is possible to find software controlling the level of the battery while the OS is running, when the computer is powered off/put to sleep, it will start charging because there is no hardware support for such feature - keeping the battery at lower level.
So in conclusion, if you have laptop different from Lenovo/ThinkPad, I think there is no way to achieve this.