Bucking 13.2v

1

1pet2_9

Active member
I just got a nice donation of big 13.2v power supplies, used for led floods. Do I need to bother bucking it to run resistive 12v pixels? I'm used to buck converters needing a minimum 2v drop, and I'm not used to bucking 50 amps' worth of current. Was hoping to just run 30 feet of wire and that that wouldn't wear-and-tear the pixels too quickly.
 
Wouldn't a couple diodes drop the voltage by 1.2v I think silicon diodes have a .6v drop. just make sure they can handle the current. I am not an electrical engineer so please get a second opinion.
 
I was thinking of using these PSU's on my 12v single-line props and switching them with NMOS fets, only switching the vdd line instead of GND. Then I don't have to worry about bucking all 55amps at once, with one converter--I need only switch one prop at a time. That might actually be a pretty sweet arrangement.
 
In reality, the WS281x chips have a very wide operating voltage. In most cases the problem that comes up is a loss of clean color. Next, if you are only using a single buck converter to regulate for 60A then you are not taking advantage of the distributed power capabilities driven by power injection. Most pixels use 20AWG (or smaller) wire. That effectively limits you to ~2A through any given segment of wire. IMO, it is more efficient to have multiple buck converters located near injection points than to try to regulate and distribute from a central location.
 
This is in reliability testing. I just ran a 30' wire and drive some 12v pixels. So far so good, but I'm worried about reducing the life. These 13.2 PSU's only have one pair of output leads, so it's convenient to run it down a 30' snake and then fan it out. I think right now that's a 12awg solid core. Adding a power nmos fet wasn't convenient.
 
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