why not use 24v to power your lights

I did this at my old house for large parts of my display. The challenge I had was that my buck converters passed through the input voltage to output when they failed, and so 24v fried a huge amount of my 5v pixels and panels :/
 
I've been doing this for a few years and had no issues.

You do need to use decent converters though. I use Mean Well for some of mine.
 
I am in the process of making some simple crowbar circuits to to sit across the convertors I am testing. Basically if the output rises over 5.6V, it'll kill the input to the converter and blow a fuse.
Changing for 12V operation would be straightforward.
If I get something usable and cost-effective, I'll release the design.
 
I bought a bunch of 12-5V converters to do the same thing as I have 5V LEDs, 12V spots, and some very long runs… they claim to fail open but who’s to know?! I’m considering running 240v and regular power supplies in the garden but I’ll have to see how it all goes.
 
They are made by Camdenboss, part # CSACTT004.

I purchased mine October last year from Element14 at $12.69 each, however they no longer stock them.
Currently available from RS Components: https://au.rs-online.com/web/p/general-purpose-enclosures/1271065
Unfortunately they seem to now be pricey at $35.39 each.

I put a few magnets on the back and had them mostly mounted up under the eaves. The transparent lid was handy to fault find a blown fuse from the ground without needing to climb up a ladder.
 
Skymaster said:
If I get something usable and cost-effective, I'll release the design.
Click to expand...
This is cut #1 at the design. Testing has proven effective, once the output hits just under 6V, the fuse is intentionally blown and power is cut.
I have had 25 PCBs delivered and required components to populate them, which would be more than enough for my show. Total cost (off memory) is around $6 per unit. This is the 3d render of it. I'll take some photos and put up a more detailed blog post about it later.

crowbar1.png
crowbar2.png
 
It would also be interesting to see what sort of leakage current there is at, say ~5.1V
 
I am intrigued by this "Crowbar" device.

Several years ago we tried running 24vdc to several of our outer devices. The DC-DC converter dropped it down to 12vdc and all was well - until the converter decided to go belly up. Loss of the remote and several pixels on the strings was our penalty. When this happened three times, all the 24vdc connections were converted to standard 12vdc (PS at the site of the remote). The converters were given to some hobby folks.

If this Crowbar device will prevent loss of equipment due to a fault in the feed, I'd be up for getting some and trying again. (There was an advantage to using 24vdc.)
 
algerdes said:
... this Crowbar device will prevent loss of equipment due to a fault in the feed, I'd be up for getting some ...
Click to expand...
It should but there are limitations. The purpose of a supply 'crowbar' is to protect against an over-voltage condition on the supply's output terminals. If something happens to the supply and the supply's output stays below the crowbar trigger voltage threshold, the 'crowbar' circuit will not add any protection. Likewise, anything happening to the supply's load, a short or over current for example, in a pixel, connector, or wiring.

Another inherent design issue is 'crowbar' circuits are or can be falsely triggered by noise on the supply's output. @Skymaster mentioned the circuit triggers just below 6 Volt so ideally, the downstream load needs or should be able to handle 6 Volt without damage.
 
Yes Terry is on the money there. If you got 48V into the input of the DC converter and it's not designed to take it, this device will do nothing to protect the converter.
It won't pick up on an output terminal short (you should still probably keep fusing for that) however the design does require the fuse on the input side. Basically that's the protection. Over voltage on the output triggers a short circuit on the input, blowing the fuse. Prior to the fuse blowing, the input will be zero volts to the convrrter, and so the output is protected.
 
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