battery powered projector

Without looking at "how to write a good question" - so it probably isn't: can anybody recommend a battery powered projector for showing movies on my iPhone?

We are starting a “make your own movies” club and meet in a yurt (no power) to share our clips. We can make the space quite dark but not completely and there are 7 of us in the club so the image needs to be be large enough for us all to see it.

I like the idea of the battery being external so that we can buy a couple and power them all up before our meeting.

Price is not a problem. We just want the one that will show the best quality picture.

Any thoughts anybody?