I'm really not sure what the voltage limits are or anything. And I have 0 experience with laptops. My firend wants me to fix up his computer, but the battery is like half dead.. I have a charger here that came with an Acer, it's the right size plug but I don't know if it would be safe to use on his comp? If I need to know the voltage limits could someone please instruct me on how to find it? Thanks. (He is using Windows XP if that helps)