If you own a MacBook and have a need to run on battery for 32 hours then there is a new product out that it just for you.
It is called the HyperMac and is made by HyperDrive. The device is really nothing more than an external battery that you can plug your MacBook into. While tethered the HyperMac can not only power your book but can also recharge the battery and charge your iPhone.
The product looks to be decent although there is a very steep price tag on the top end model coming in at around $600 for the 222Wh flavor.
Take a look here
Power your MacBook and any USB device simultaneously
HyperMac External Battery comes with a USB 5V/1A Power Port so you can power any USB device (e.g. iPhone) individually or simultaneously with the MacBook. MacBook regards the HyperMac connection as a connection to the original power adapter. Not only does HyperMac provides power for the MacBook, it charges the internal battery as well. Check the HyperMac battery level anytime with the lighted indicator.