i have a old projector box ,that i want to modd into a 100 watt pencil bean spotlight.

i have decided to convert a old projector into a spot light .all advice would be appreciated .
the front lens is held in a telescopic tube. top and bottom of box has holes that i can uttilize for venting/fans.
guess the next step is to take a photo of my raw materials,and hopefully someone will tell me what else will best suit my needs.
i am hoping i can spend less than £40.
Already have batteries ,3x12v 18ah cla’s ,and have ordered a 100w led 32-36v(£4.83).