Crenova XPE660 Upgraded Home Entertainment Video Projector - Full 1080P HD Supported - 5,000 Lumens Create Vivid Brightness - 1280X800 Native Resolution Gives Big-Screen Images with Unmatched Clarity

Q: How well is picture outside with some sunlight, under a patio?

It works well with some light in the pation. Bright enough.

Q: Is it good for classroom? Excel, powerpoint, presentations, ect

Yes, I use for church Sunday school, it is very good.

Q: How do you open the remote for the batteries?

At the bottom narrow end you'll see a small slot, like a flat screw driver would fit in. Using your finger nail, flat screw driver, or butter knife in that slot push it downwards and the bottom will come off. Its a little tough to do. Its held on strongly with multiple plastic snaps, but if you give it steady pressure it will come off and you'll see the batteries.

Q: I can’t get the sound to come on at all. Does anyone know how to fix this issue?

On the remote press the menu button and you'll be at the Picture Options menu, then press the round circle on the right side lightly one time to go to the next screen, Sound Options. In that list the bottom choice is Sound Options, Sound Normal will play sound from the projector. Sound Line plays it from the 3.5mm audio out jack on the side of the projector. Sound Box I haven't used yet, but maybe that is for the USB output port.