How many batteries should the enclosure hold?
Should we just take up all the unused space with room for battery modules?
How many external batteries should we support?
Types of Lithium-ion Batteries
http://batteryuniversity.com/learn/article/types_of_lithium_ion
http://www.batteryspace.com/lifepo4-26650-rechargeable-cell-3-2v-3300-mah-19-8a-rate-10wh---un38-3-passed-ndgr.aspx
http://www.batteryspace.com/limnni-26650-rechargeable-cell-3-7v-4000-mah-4a-rated-14-8wh---ul-listed-un38-3-passed-ndgr.aspx
http://shop.battex.cz/pdf/400434LM.pdf