Optoma Bb-Pk3alis 1410 Mah Battery For Pk201 & Pk301
Bought the PK 301 projector on e-bay, and always like to have an extra battery just in case the first cannot get through a full movie.  I had the old 101 projector and had extra batteries for that one, so I understood what needed to be done if you are without power and desperate for a movie.  The 301 is the only one that is compatible with a Macbook Air.  So, I fired this extra battery up, have now had great parties with full length movies.  At about 45 minutes at a good place, call intermission and load th