That power supply will likely work. You would have a little bit more reserve if you could find a 350W one for around the same price. Not sure where you are located, but generally here in the US a lot of people go with the LRS-350-12. The RSP model seems to be a slightly better model, but generally not seen here. If you can find a decent price this looks like an option as well: RSP-500-12
This was some info I found about the 2 models:
"the RSP-320-xx has PFC (Power Factor Correction). The LRS-350-xx supplies do not.
The RSP supply also supports an input of 85 VAC to 264 VAC whereas the LRS-350-xx has a physical switch to select the normally seen 120 VAC or 240 VAC. There is better regulation on the RSP as well as some other subtle differences in specifications. The LRS-350-xx is essentially designed for a rather typical industrial automation/control environment where the RSP series includes that and adds test/measurement equipment. Essentially, the RSP is a higher quality tighter specifications designed power supply."
Thanks for your inquiries regarding both models.
I’m located in Madrid ,Spain
Looking at the local Mean Well supplier, for model LRS-350-12 it’s mentioned :
"This power supply does not meet the harmonic current requirements outlined in the EN61000-3-2 standard. Do not use this power supply in the following conditions:
Equipment used within the European Union."
On the other hand based on your indications RSP model seems a little bit better so I will go for It.
Now I have everything clear . Thanks for guiding me
It’s sort of funny that I stumbled on this topic today.
I’m testing out a NodeMCU shield I designed that will handle the problem. Just received the boards a couple days ago and have a few prototypes soldered up.
Whether 12V or 5V is supplied, the output is the same as the input but the NodeMCU only receives the voltage needed to operate and won’t explode. It should handle plenty of amperage needed to power many strips. (I haven’t tested the max limits yet)
Power for your LEDs comes from your power supply via appropriate wiring.
Data for your LEDs comes from your data supply (MCU) via appropriate wiring.
Appropriate wiring for power is not the same as appropriate wiring for data and vice versa.
I know there are a number of boards out there (including your own) that combine power connections on a single board with the MCU for ease of use. That’s fine as long as you keep in mind point 3), the wiring you need to handle 30A of current is very different from what you use to make your data connections. In addition, it’s not a trivial task to design PCB copper to handle that kind of current properly.
Of course your setup may have completely different requirements.
Hi again Jinx reviewing your connection diagram I have some additional doubts .
For connecting athom controller to led strip WS2815 I was thinking that I should connect it directly using a JST connector as shown on the attached photo
But then looking at your diagram what I understand is that I should not use the JST connector and that I only have to connect GND (white cable) DA (blue cable) and CK (green cable) from the controller to the strip so NO positive red cable should be used, similar to the attached photo
Please could you confirm me if no red + cable should be used?
In case I used a red (+) from controller to strip, could current from power injected at the beginning of led strip go backwards through the controller and damage it?
For power injection should I unsolder thinner default red (+) and white (GND) cable that come with the strip, and then solder the thicker AWG 18 cable that I’ve bought for power injection to positive a GND pins of led strip or can I solder the thicker AWG 18 cables to the thinner default cables that are already soldered to the LED strip
For intermediate and end power injections is it preferred to cut end strip cables and connector and solder AWG 18 to their corresponding pins of led strip? Or solder thicker AWG 18 cables to thinner (+) and GND default end cables already soldered to led strip pins?
Thanks again in advance for your clarifications and advice.
That picture (bare wires connected directly to the strip) is the preferred method if you connect the main power lines directly to the bare wires. In that configuration power required for the LEDs goes directly to the strip and power for the controller goes through the JST connector. The controller will only take the power it needs (< 0.5A) so the JST connector is not an issue.
This highlights one of the common misunderstandings w/LED setups - the controller does NOT “push” power to the LEDs. The LEDs consume as much power as they need from their power lines according to the colour and brightness the controller tells them to display. Similarly, the controller consumes as much power as it needs, although that’s a very small (mostly constant) fraction of what the LEDs will use.
The whole barrel plug/JST connector issue comes about when people try and wire the strip through the controller. That’s not inherently bad, it’s just that many controller boards aren’t designed for the current the LEDs may require. Better to handle your power lines separately and appropriately.
Keep those smaller wires short (<5cm) and they can be used as a convenient way to connect your 18AWG wires. The larger wire can be tough to connect reliably to the flex strip without wrecking things.
Much depends on your soldering skills.
For multiple injection points I’m a bigger fan of intermediate spots rather than just the ends. The more evenly you can space the power distribution throughout the entire strip, the more even the voltage for the whole install. You can use the same idea of soldering short pieces of 20AWG stranded wire directly to the strip to make the 18AWG connections easier and more reliable. Note - injections should always be both + and Gnd wires at each spot.
WS2815 does not have CLK it has Backup Data. Backup data needs to be tied to Ground (-) not to the CLK pin.
If you connect the + to the controller you will be back to the possible problem of overloading the traces on the circuit board, as it is not rated for the high Amp draw you (possibly) will have, unless you have the feed to the controller fused at the proper Amperage to protect the board and JST connection. I think JST is rated at something like 3A.
With all things correct and with proper injection you should not have an issue with any one power wire pulling full amp load, but there is always the possibility of bad connections, blown fuses or who knows what compromising connections and if all are not fused you are leaving yourself open to 1 pulling a high load if something were to compromise any/some others. Or if you had a short circuit close to 1 connection it would likely pull excess current close to the short before those further away.
As divsys said injections at mid points provides the most balanced power, but can be more of a headache than end injections depending on strip location real-estate, soldering skills, or if using IP67 coated strips (and your pic shows coated strips).
So based on your suggestion I should connect white (GND) a blue (BI) cables from JST connector to the GND output of the controller , green cable (DI) to Data 1 from the controller . Red cable (+) shouldn’t be connected since I would directly inject the power from power supply (after going through the 5 amps fuse)
Then connect the JST connector with the Led Strip connector , as shown on the next two photos
Please could you confirm me if this would be the correct wiring.
Finally is this video it is recommended how to connect the backup signal from WS2815 to the controller . It’s suggested that in case led strip is far away from controller in other to avoid interference not to connect the backup signal together with the GND at the output of the controller but to the GND as close to the led strip pins.
But if controller and led strip are close (close) BI and GND could be directly connected to the GND out of the controller (this would my case)
I don’t if you agree with this suggestion
Looks good to me. You could also connect your power to those extra red and white injection wires vs running through the JST.
If there will be some distance from your controller to the strip then yes you could eliminate some interference if connecting the ground and backup data by the strip.
Don’t have that live wire dangling! At least snip off the exposed copper. And better still remove the wire from the connector or put a small piece of heart shrink on the end.
Thanks for your confirmation Jinx.
Artacus thanks for your safety tip I will eliminate the red wire from the JST connector, since as Jinx mentioned I will inject power through the white and red extra cables already soldered to the led strip.
Again thanks you all for your patience
Regards
I am amazed at how many people do not understand fuses. Fuses protect the upstream circuits, not your LED strip.
The basic goals of circuit protection are to 1) localize and isolate the condition or fault and 2) prevent and minimize any unnecessary power loss.
A correctly coordinated system would isolate the fault condition as close as possible to the source and leave the rest of the system up and running as usual. In other words, if you drop a screwdriver on your PCB and short out a few things, the fuse will blow- isolating the fault (screwdriver shorting out the PCB) from the upstream circuits, like the power supply. The fuse does NOTHING to protect the PCB from the screwdriver.
Fuses and circuit breakers are protection devices and exist to protect components upstream of the protection device. Your master circuit breaker may be 100 or 200 Amp and below that a bunch of 15, 20 and even some 30 Amp breakers. If you have a 15 amp circuit that experiences a failure, the breaker or fuse on the appliance will remove the failing device from the upstream circuits to protect them. The failing device is already toast, so there’s no protecting it. All other circuits are protected because the failure path has been broken. Thus the name: “Circuit Breaker”.
