u/Idea_Ranch

Hello, experts. I'm designing — then must build — a 24VDC power setup for for some lighted field props for a HS marching band show this fall.

(Background: I've built/powered lights on props before, constructing robust wiring setups in outdoor-rated enclosures. But those were all single-battery 12VDC-10A systems.)

One large prop uses 24VDC-50A for the lights. So I need large (car-size) batteries. There's no space for a 24V battery (plus, those cost a fortune) so dual 12V batteries makes more sense. Safety rules require AGM or LiFePO4 batteries, which is fine w/ me but not cheap.

I know how to wire two 12V batteries to get 24V, and I'll use a large outdoor-rated battery cutoff switch to power on the lighting controller.

My problem: How wire this setup to also use the 12V battery chargers they already own, in a clean and user-friendly way?

The setup shown in these diagrams, using 4 switches, should work well enough. Until someone flips the wrong switch at the wrong time. (It also looks a little clunky and overcomplicated, tbh.)

Here's the setup with the lights ON, chargers off:

DMX Lights ON; Chargers disconnected

Here it is with the lights OFF and the batteries charging:

DMX Lights OFF; Chargers connected

So ... the circuitry isn't that complicated, but 4 switches is a LOT. Seems like there should be a simpler/smarter way to do this.

My biggest concern is: this is a high school band, and the students will be responsible for using the props during the season. I'm wishing for a simpler system where it's impossible — or at least difficult — for someone to accidentally close switches 3 or 4 while the chargers are connected (and powered). Or to forget to close S3 before entering the field.

There are fuses and a circuit breaker, as you can see. But if someone blows a fuse minutes before a performance, there may not be time to open up the (hidden) weatherproof enclosure and replace it.

There are 24V battery chargers, of course. But the band is already spending many thousands on these props ... so I'd love it if there's a way to save a few hundred on new chargers (and to clean up the system before I start building it).

Any/all suggestions are welcome. Thank you in advance.

[EDIT: Fixed typo]

I’m designing a lighting system for a marching band’s fall show. It’ll be mostly LED strips (some pixel-controllable, some analog). But they’re mounted on various field props that move all over the place during the show. Therefore battery power and wireless control are the only option.

I’ve used WiFi to control addressable LEDs for a couple of band-adjacent ensembles the past two years (Indoor Percussion and Winter Guard). WiFi worked okay after LOTS of tweaking. Specifically: It always worked great in rehearsals, indoors or out. But once there’s an audience in the gym or arena, lots of interference/glitching. After adding 5G external bridges to each WLED fixture, I got things to work fairly reliably for those shows (where everything is within 80’ of everything else.)

So while I know how to get WiFi to work in a relatively small space, now I gotta cover the whole football field. Before I go dropping $3K on a full suite of Ubiquiti Nanostations (one for each prop) and 2-3 Ubiquiti WiFi APs on the sidelines, I wanted to ask whether there is a better solution for wireless E.131/SaCN control.

I know there used to be something that worked for that: Back in 2016 I was handed a set of 40 cheapo wireless DMX boxes (each about 3x3x2”) and asked to figure them out. (Zero lighting experience before then.) Once I managed to understand DMX basics, I bought Luminair for my iPad and somehow pulled it off.

The thing that struck me about those old, cheap tech boxes is that they WORKED, even across long distances. It was hard to find documentation, but from what I was able to gather, they acted as repeaters for one another… as long as at least one of the boxes was close enough to the sideline controls, all of them talked to each other and shared the same DMX data. All without having to set up my own Wi-Fi network or other base station. (I used an eDMX ethernet adapter to send the DMX to one of the cheap boxes next to my iPad. That was the whole network. (I think they used the old 900 MHz cordless phone spectrum.)

I’m at the drawing board stage now so this is the time to look at different/better options (other than WiFi) for lighting control. Would be grateful for input/suggestions.