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mutleyrover
01-03-2015, 07:28 PM
I'm finding myself going round and round in circles thinking about powering my Christmas lights. So far I haven't yet had the time to get this hobby off the ground, maybe 2015 will be my year. However, I do have many questions!!

I'm looking at building a Renard Plus 32 or a Renard 64XC controller so will therefore need separate SSRs. Most of the light sets I have here (in the UK) are LED strings with fixed LEDs that can't be changed. They are low voltage and come with a plug pack (wall wart) that in general provides 24V DC.

Rather than have multiple wall warts I want to power more sets with fewer power supplies. My understanding is that I can use a Switched Mode Power Supply such as the Mean Well NES-350-24 to provide the 24V DC that I need to power a number of sets, as long as I stay well within the output current of 14.6 amps. Is my assumption here correct?

Also, I therefore assume that as most of my lights run on 24V DC, I would therefore use DC SSRs and provide power to them from the SMPS, with each SSR running 4 strings (channels). Am I thinking along the right lines, or is that just a load of rubbish??

I've added a couple of pictures showing the power supply I mean and also an example of the information given on the boxes of my LED light strings.

Thanks in advance for any help!!

m00dawg
01-03-2015, 07:55 PM
I'm still new at this myself but yes I think you are on the right track.

One thing to keep in mind is voltage drops if you are running long cables. The drop will depend on the length and gauge of the wire and the amperage running through it. There are some calculators (http://www.marinewireandcable.com/p/voltage-drop-calculator.html) online you can use to get an idea. There is also some good info on the wiki (http://www.doityourselfchristmas.com/wiki/index.php?title=Power_Supplies#Wire_Sizing_in_Pixe l_Systems) though it is more focused on 5V and 12V. The principles are generally the same.

You may also want to make sure your LEDs are dimmable using DCSSR's. Most are but it can't hurt to check before you buy a lot of lights. And if you're buying a lot of lights, I would hunt around here to see if you might be able to get lights cheaper by jumping in our a pre-sale or group by. I dunno how many happen in the UK but you can end up saving quite a bit of money that way.

Hopefully some seasoned folks around here can give you better advice, but hopefully the above was at least somewhat helpful ;)

mutleyrover
01-04-2015, 07:42 AM
Thanks for your supply. It's nice to know I'm thinking along the right lines!

I don't think I would be running cables that were that long so hopefully voltage drop shouldn't be too much of a problem. As for the LEDs I have, I'm not sure if they're dimmable or not. At this moment in time I have no controller built to be able to test them so I'll have to bide my time, but fingers crossed they are. I've got about 70 sets at the moment, all be it fairly short strings, so I hope they don't prove to be useless. I'm assuming DC SSRs are the right sort to use rather than AC SSRs when I'm using a DC Power supply.

Also, I noticed that some of the LEDs I have say they are 25V DC. Would it make much difference if these were plugged in to the same SMPS providing 24V DC, or should you use a separate SMPS adjusted to provide 25V DC. I'm no electrician so I'm learning as I go....

Better get shopping for things I guess!!

m00dawg
01-04-2015, 12:53 PM
Yes, if they are DC lights, you need DCSSRs, though take note that you would hook the lights directly up to the SSR which you will then hook into the power supply. Note that some controllers include SSRs and some do not, so you'll want to figure out which setup works best for you. Depending on how you have things setup. Just be sure that, if you go the integrated route, you get a controller that has integrated DC, not AC, SSRs.

As far as 25V vs 24V, that's actually a good question. It depends on how things are wired up as to what effect that will have, but it will likely just make things slightly dimmer on your 25V strands. If you have a voltmeter/multimeter, you can check what voltage is coming off your 24V and 25V PSUs to see how big of a difference it is. Be aware that some PSUs require a load applied to them to give you accurate readings (so basically you have to measure the voltage with the light strands connected). You could also just try connecting your 25V strands to 24V if they are similar to each other and see what happens, though I would do the multimeter tests first.

P. Short
01-04-2015, 01:12 PM
Thanks for your supply. It's nice to know I'm thinking along the right lines!

I don't think I would be running cables that were that long so hopefully voltage drop shouldn't be too much of a problem. As for the LEDs I have, I'm not sure if they're dimmable or not. At this moment in time I have no controller built to be able to test them so I'll have to bide my time, but fingers crossed they are. I've got about 70 sets at the moment, all be it fairly short strings, so I hope they don't prove to be useless. I'm assuming DC SSRs are the right sort to use rather than AC SSRs when I'm using a DC Power supply.

Also, I noticed that some of the LEDs I have say they are 25V DC. Would it make much difference if these were plugged in to the same SMPS providing 24V DC, or should you use a separate SMPS adjusted to provide 25V DC. I'm no electrician so I'm learning as I go....

Better get shopping for things I guess!!

Two things to bear in mind:

The peak voltage for a 24VAC signal is around 33V (24V * 1.4), which is greater than the output of your 24VDC supply.

However, potentially offsetting the decreased voltage of the DC supply is the greater duty cycle. Depending on any filtering circuitry included in the 24VAC LED string, the turn-on voltage of the LEDs involved, and whether it is a half-wave or full-wave string, the duty cycle and hence the brightness of the LEDs may vary from when you use them with the AC transformer. They may be brighter or they may be dimmer, the only real way to tell is to try them and see what happens.

mutleyrover
01-04-2015, 03:50 PM
Yes, if they are DC lights, you need DCSSRs, though take note that you would hook the lights directly up to the SSR which you will then hook into the power supply. Note that some controllers include SSRs and some do not, so you'll want to figure out which setup works best for you. Depending on how you have things setup. Just be sure that, if you go the integrated route, you get a controller that has integrated DC, not AC, SSRs.

My plan is to build a Renard board with off board SSRs. my thinking is either the Renard Plus 32 or the Renard 64XC although I can't decide which is best!!!

mutleyrover
01-04-2015, 03:59 PM
Two things to bear in mind:

The peak voltage for a 24VAC signal is around 33V (24V * 1.4), which is greater than the output of your 24VDC supply.

However, potentially offsetting the decreased voltage of the DC supply is the greater duty cycle. Depending on any filtering circuitry included in the 24VAC LED string, the turn-on voltage of the LEDs involved, and whether it is a half-wave or full-wave string, the duty cycle and hence the brightness of the LEDs may vary from when you use them with the AC transformer. They may be brighter or they may be dimmer, the only real way to tell is to try them and see what happens.

Now I'm confused!! The LED strings I've got have a variety of transformers (wall warts) that all seem to have different labels. My thinking was that LEDs are DC so all of these transformers take our 240V AC supply and change it in to a low voltage DC supply, which then powers the LEDs. That's why I was under the impression that a SMPS would work well to power a number of sets from one supply.

The pictures show just a couple of the wall warts that come with my LED strings... so many different figures, some 24V, some 30V although they don't say whether the output is AC or DC (apart from one!).

m00dawg
01-04-2015, 04:49 PM
At least in the states, I tend to see ~ indicating AC and the === being DC. A quick test with a multimeter will tell you though, so I would do that regardless of what the labels say to know for sure.

The LEDs themselves work of DC though you can have both AC and DC LED strands though their wiring often differs between the two types. To my knowledge, you can't mix and match AC and DC SSRs, so you need to know what you're actually dealing with before you can figure out which type you need.

On the controller side, though, since you want to use external SSRs, that won't really change things much. Either of your choices should work, and don't forget about the group by going on for the Renard SS boards. I'm not sure if that includes the UK, but it's worth checking out since it can save quite a bit of money.

mutleyrover
01-04-2015, 05:04 PM
Figuring out what I'm dealing with in the first place seems to be the hard part!! I really need to crack on and build a controller so I can start some tests! I have ordered a Mean Well SMPS (pictured in my original post, so I guess I can connect a set directly to that for a trial run....

m00dawg
01-04-2015, 08:22 PM
If it were me, I would invest in a voltmeter. In the states they can be had for as little as $10 and that would avoid risking your LED strands. A controller won't get you much if you don't know what sort of SSR to purchase, after all.

If you're going to build a controller, you should have a voltmeter anyway to be able to test to make sure the correct voltage is going to the correct pins, etc.

mutleyrover
01-05-2015, 02:00 PM
I have a multimeter - just need to get it out of the box a little more often!!

algerdes
01-05-2015, 05:11 PM
From the four pictures you presented, 3 are AC output, the fourth is DC.
(My guess, based on much experience at getting it wrong when I was a much younger man.)

A very quick tell is to look downstream from the controller. If there is a rectifier inline, you probably have AC out of the power packs.
(LED lights by their very nature are DC, therefore only use one side of the wave.)

mutleyrover
01-06-2015, 02:12 PM
From the four pictures you presented, 3 are AC output, the fourth is DC.
(My guess, based on much experience at getting it wrong when I was a much younger man.)

A very quick tell is to look downstream from the controller. If there is a rectifier inline, you probably have AC out of the power packs.
(LED lights by their very nature are DC, therefore only use one side of the wave.)

Having looked again at the pictures I can see what you mean now about the secondary output. 3 of them show the wavey line for AC and I can see the other one shows the solid and dashed line for DC. I'm learning all the time!! I have so many of these power packs and I really want to reduce them to a few power supplies that I can feed directly in to the SSRs, therefore not needing one of these wall warts on every single output from the SSRs.

Am I correct in thinking that if I match the output of the wall wart with a different power supply that should work okay. For example, if I have 4 LED sets all with their own "DC output" wall wart (as pictured) could I use an SMPS instead which provides 30VDC to a DC SSR which then has a single string of the LED lights from each of the 4 outputs. And as for the LED sets with the "AC output" wall warts could I use a toroidal transformer, which provides 24VAC to an AC SSR and then have a single LED string of each of the 4 output channels. Is this too simplistic or does that all make sense??

m00dawg
01-07-2015, 09:34 AM
I think it would be unwise to plug wall warts directly into an SSR - at least if you were going to be doing any dimming. Rather you would match the output power of the SSR itself with what you need. If you need 24VDC, use a DCSSR and a 24VDC power supply into it (A nice SMPS would be fine here). If you need 24 VAC, use an ACSSR and a 24VAC transformer to it.

mutleyrover
01-08-2015, 04:55 PM
From the four pictures you presented, 3 are AC output, the fourth is DC.
(My guess, based on much experience at getting it wrong when I was a much younger man.)

A very quick tell is to look downstream from the controller. If there is a rectifier inline, you probably have AC out of the power packs.
(LED lights by their very nature are DC, therefore only use one side of the wave.)

I've looked at some of the lights I have and from what I can see the ones that have a power pack with AC output do have a block in the wire. I've attached a picture to show you what I mean. Is that likely to be the rectifier?

masterful
01-09-2015, 02:45 PM
Hi there.
That's a good question. I bought a lot of led strings last year that rusted up good. They had a multifuntion controller connected to them. Not one had the block as shown though. I need to research more

mutleyrover
01-09-2015, 04:26 PM
I'm going to guess that your lights had power packs with a DC output. As I said before, I think the block in the wire (as picture) is to do with converting an AC output from the power pack in to a DC supply for the LEDs.

Can anyone confirm if this is correct??

MartinMueller2003
01-09-2015, 04:58 PM
I think it would be unwise to plug wall warts directly into an SSR - at least if you were going to be doing any dimming. Rather you would match the output power of the SSR itself with what you need. If you need 24VDC, use a DCSSR and a 24VDC power supply into it (A nice SMPS would be fine here). If you need 24 VAC, use an ACSSR and a 24VAC transformer to it.

There is no problem using the output of an AC wall wart to power an AC SSR (Lower voltages work while higher voltages than the specified design voltage causes magic smoke). Dimming will require the PWM version of the software. So if you insert the AC SSR between the Wall Wart and the LED string, you should have functioning control, as long as the string was of the constant ON type. If there is a multi-function control box between the wall wart and the string then you will have to bypass the control functions in that box. FYI: I had some of these strings and replaced the multi-function control with a full wave rectifier bridge and it worked very well.

I would also like to correct a statement made in an earlier post: For the 64XC and any other controller that uses external SSRs, it IS possible to mix and match DC and AC SSRs. I myself run 8 channels of AC and 32 channels of DC on my Ren 64XC. NOTE: Controllers with integrated SSRs cannot mix and match on the same controller.

mutleyrover
01-09-2015, 05:57 PM
There is no problem using the output of an AC wall wart to power an AC SSR (Lower voltages work while higher voltages than the specified design voltage causes magic smoke). Dimming will require the PWM version of the software. So if you insert the AC SSR between the Wall Wart and the LED string, you should have functioning control, as long as the string was of the constant ON type. If there is a multi-function control box between the wall wart and the string then you will have to bypass the control functions in that box. FYI: I had some of these strings and replaced the multi-function control with a full wave rectifier bridge and it worked very well.

I would also like to correct a statement made in an earlier post: For the 64XC and any other controller that uses external SSRs, it IS possible to mix and match DC and AC SSRs. I myself run 8 channels of AC and 32 channels of DC on my Ren 64XC. NOTE: Controllers with integrated SSRs cannot mix and match on the same controller.

In your post you talk about a full wave rectifier bridge. Is that what the things are likely to be in my LED string wiring (post #17)?

m00dawg
01-10-2015, 02:21 PM
There is no problem using the output of an AC wall wart to power an AC SSR (Lower voltages work while higher voltages than the specified design voltage causes magic smoke). Dimming will require the PWM version of the software. So if you insert the AC SSR between the Wall Wart and the LED string, you should have functioning control, as long as the string was of the constant ON type. If there is a multi-function control box between the wall wart and the string then you will have to bypass the control functions in that box. FYI: I had some of these strings and replaced the multi-function control with a full wave rectifier bridge and it worked very well.

Would that depend on the wall-wart? A DC linear regulated wall-wart, for instance, I would think would behave differently over an AC one. No clue what a switchmode wall-wart might do in that case. Someone feel free to school me on the topic :)

masterful
01-10-2015, 03:50 PM
A switch mode power supply is specifically designed for DC output. Some have variable output voltages from 3volt to 12 volt

masterful
01-11-2015, 04:33 AM
Having another look that looks too small to be a rectifier. Last season I bought some acrylic figures. They had a 24v DC output transformer and one those white links in the cable. So my thoughts are they are a moulded in line cable connector.

m00dawg
01-11-2015, 12:14 PM
A switch mode power supply is specifically designed for DC output. Some have variable output voltages from 3volt to 12 volt

Right but I don't know what the outcome would be for attaching it to an AC SSR and, likewise, a DC SSR. Switchmode PSUs that offer a wide input range still offer a consistent output range meaning the dimming wouldn't work as expected. Also, a linear DC PSU is going to behave differently as well.

I don't know enough about using SSRs with these types of devices, so I can't say if it's safe to use them with SSRs. My opinion? Wall-warts are a pain and I find a lot of failure rates in the switchmode ones. Seems like using the SSRs and PSU to what the lights want and getting rid of them entirely is still a better option where possible.