MacBook External Battery solution.
If you’re like me, then you’ve found you self in a situation where you needed to use you MacBook Pro out in the field, there was no access to AC power and you couldn’t depend on the internal battery to last.  There have been times when I’ve wanted to offload P2 footage while drive from one location to another, or worse, while out in the middle of a field or in the woods somewhere.  I think I may have found a nice solution to my problem.  Hawk-Wood (a UK company) offers a line MacBook battery adapters that can run off of V-lock, Sony NP-F or Sony BPU style batteries. All the adapters come with an XLR 4-pin to MagSafe cable and are able of running your MacBook or MacBook Pro. With a MacBook Air, it’ll even top off your battery as well.  (Runtime depends on the batteries you use)