I'm trying to find a movie my college girlfriend and I saw in the drive in in the 80s. (probably 85-87). It was a drive in so not a brand new movie.

I remember it may have had a vibe like "rick N Roll High School" with the Ramones. The main thing I remember is when a student got busted there would be a "rubber stamp" across the screen that said DETENTION

I really want to find it for nostalgia's sake. It was raining and we had a great time* at that drive in. 😉

I frequently go camping at festivals or other large events. I have this idea that if I had a laser that shined straight up in the air I could use it as a beacon to find my spot and/or help other people find me. Some of these festivals are huge.

So......

My (tentative) goal is a laser in the 532-555 nm range. Ideally I'd like a small unit that is battery powered and will run for hours on a single battery. I am thinking a class 2 ( < 1 mw ) will be enough and keep it relatively safe. Naturally I would mount it high up to prevent curious people from looking directly in to the emitter.

I am handy with electronics, soldering, etc, I am mostly looking for general advise and even a recommendation on components.

Edit: I should note, it is fine if it only works at night.

I just took the inaugural trip in my new RV (Aliner Evolution). When I stopped on the road for a break I walked around the trailer to visually inspect everything and the battery had nearly slid off the rack!

The battery is in the typical plastic battery box and the strap around the box lid, box, and frame was as tight as I could get it when I left. I noticed that the battery rails in the trailer go side to side, but there is NOTHING to stop the battery from sliding sideways except friction.

To finish my trip I rolled some duct tape to make some double sided tape and that seemed to secure the box from sliding (with strap of course). But this is obviously a temporary kludge.

Are other trailers like this? What is a better fix to secure the battery? Preferably something that looks "tidy"

My camper (ALiner Evolution 15LG) came with an 80AH 12V AGM battery. When this battery dies I think I want to upgrade the lithium (for more off grid power, I am hoping to run the refrigerator off grid. )

The camper has 2 - 200 watt solar panels on the roof. They feed a Victron smart solar controller MPPT 100 / 30 Charge Controller. The solar controller can be set to lithium.

The power center is a WFCO technologies WF-8735-AD Power Center which claims it can auto detect the battery type. (I also know it can be set manually if auto detect fails). It supports lithium.

So... it sounds like if I swap the battery, configure the power center, and configure the solar controller I am in pretty good shape?

Somebody mentioned that I should get a DC to DC converter for the 7 pin plug wiring. I'd like to know more about that.

Am I forgetting anything?

My camper (ALiner Evolution 15LG) came with an 80AH 12V AGM battery. When this battery dies I think I want to upgrade the lithium (for more off grid power, I am hoping to run the refrigerator off grid. )

The camper has 2 - 200 watt solar panels on the roof. They feed a Victron smart solar controller MPPT 100 / 30 Charge Controller. The solar controller can be set to lithium.

The power center is a WFCO technologies WF-8735-AD Power Center which claims it can auto detect the battery type. (I also know it can be set manually if auto detect fails). It supports lithium.

So... it sounds like if I swap the battery, configure the power center, and configure the solar controller I am in pretty good shape?

Somebody mentioned that I should get a DC to DC converter for the 7 pin plug wiring. I'd like to know more about that.

Am I forgetting anything?

EDIT: MORE INFO ON DC-DC CONCERTER CONCERNS

What I was told (but am not sure is true) is that a lithium battery could draw enough current from the 7 pin connector / tow vehicle to blow a fuse in the tow vehicle or even cause some heating problems on the 7 pin connector wire and that the DC-DC converter would limit the current.

Also, while parked (say... for lunch) and connected to the tow vehicle, a lithium battery could pull enough power to deplete the tow vehicle battery. (if I buy a large lithium batt like 300 ah)