Let’s say you have several hundred WS2813’s powered by two separate power supplies located at/near the endpoints. I know you are supposed to separate the 5V signal between the power supplies. But what is the risk if you don’t? I.e. what might you expect to happen – fire risk? flaky signals? jittery LEDs?
I’ve done this before at one installation and had no problem. But I’m encountering it more, including places where it’s not convenient to separate the 5V.
Apologies if this has been covered already, I did some searching but didn’t see it addressed directly.
(@Yves_BAZIN we discussed this in another thread but I thought I’d pull this point out into its own discussion.)
I managed to burn out a couple of 5V battery packs by by connecting their positives together. It’s simple though, just break the positive rail in the middle.
More data – I posed this to an electrical engineer friend and here is what he said. (Note, in one of my installations, it will be difficult to break the positive rail in the middle due to where it’s located.) . I’m not trying to disagree with what you posted @marmil , just trying to assess how risky it is, and what are the specific risks.
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"On both sides, you have the same supply.
If they come from the factory at nearly the same voltage OR you adjust them to the same voltage, you will have no problems because there is a big resistor between them. There is no risk of fire or problems because of this alone.
The current may come more from one supply than the other and one supply could over current fault.
The supplies see the same temperature and other conditions, so they should be balanced.
One thing to note is that if one supply fails, you have to have the wires the correct size for the extra current OR the remaining supply has to to limit current or shut off."