I'm trying to find the definitive answer on this. I have an extra 60 watt MagSafe from my previous 13" 2009 MBP. I have two locations in my house I will use my MBP and would like to not have to haul around the power adapter. Can I use my extra 60 watt MagSafe instead of my 85 watt one? Even if this means using partial battery power to make up for the extra 25 watts I would be okay with it. Eventually I will buy another 85 watt one, but in the short run I'd like to use it.