How To Power CMB-16D DC Card

[WeissWelsh]

Hello everyone,

I am a complete idiot when it comes to this stuff, so please don't assume I have any basic knowledge of how to do this.

All I want to know in this particular posting is if I have what I need to do this. A later posting will ask for more specific help.

I purchased a CMB-16D DC Card awhile back for controlling a bunch of WireKAT LED M16 Flood lights.

Specifically, I have a total of 160 MR16's (40 Blue, 40 green, 40 Red, 40 White.) I was hoping to run all of them off of a single CMB-16D DC Card. There will be 4 channels for each color, which means each of the 16 channels will power 10 MR16's.

I read on one of the forums that each MR16 needs .2 amps. Is this correct? If so, then the CMB-16D DC card should be able to handle all 160 Mr16's (.2*160=32 amps --- 16 amps per side and 2 amps per channel.) I believe that is within the DC card's limits.

So, I think this means I need a DC Power supply that is at least 32 amps. Correct?

I have in my possession a CoolMax V600 ATX Power supply. I attached a photo of the label that's on the side of the power supply. Will I be able to use this power supply for what I want to do? How many amps are available for me to use from this power supply?

On a side question: On the picture of the label, it shows +12V1-18A, +12V2-18A, and +12V3-15A. I'm assuming these are the numbers I'm concerned with. The lable seems to indicate that those three values add up to 450 Watts. This is where I'm confused. Those 3 values add up to 51 Amps (18+18+15.) But at 12 volts, 450 Watts is only 37.5 Amps.... not 51 Amps. What am I doing wrong.

Thanks for your help.

Bob

Attached files

[Max-Paul]

I had to go back and review the specs for the DC controller on the LOR site. Without heat sink on the transistors you can have as much as 4 amps each. Although there is a limit to the amount of current on the bank of 8 channels which is 20 amps. So reviewing your plan is to have 2 amps per channel. So you are ok there with only 50% loading per channel. And 8*2=16 amps per bank. So your ok there too with only 80% loading if all 8 channels are on at a time.

As for your P.S. thats 450W Max. So you can not max out the current for all of the different voltages. It would have to be a balance of the three 12 volts current draw. Example V1 could be 18 and V2 can be 18, but V3 can only be 1.5 Amps. Or 12 + 12 + 13.5 Amps. Any combo that is less than or equal to 37.5 Amps. But also notice that if this was used in a computer you also have to balance all 3 voltages to equal less than 581.5 amps.
Clear as mud?

[Steven]

Since you have 4 colors, you probably won't be turning them all on 100% at the same time, so I think that power supply should be sufficient.

Your best bet is to connect +12V1 to one side, and +12V2 to the other side.

If you want to split the power even more, you could wire the anode (positive) from some (1/4) of your lights to +12V3, but that's not really necessary. That's right - you can connect a light (channel) to any 12V source. It doesn't have to be the supply on the same side of the board. If you really wanted to, you could get sixteen +12V, 2A wall-wart power supplies and use one for each channel. You just wouldn't use the positive screw terminals on the DC board.

As to the durability of the power supply, almost all power supply failures, and most electronic failures in general are due to overheating. As long as the power supply remains cool, it should continue to work fine, even if it's a little overloaded.

[WeissWelsh]

user=11516]Max-Paul wrote:

I had to go back and review the specs for the DC controller on the LOR site. Without heat sink on the transistors you can have as much as 4 amps each. Although there is a limit to the amount of current on the bank of 8 channels which is 20 amps. So reviewing your plan is to have 2 amps per channel. So you are ok there with only 50% loading per channel. And 8*2=16 amps per bank. So your ok there too with only 80% loading if all 8 channels are on at a time.

As for your P.S. thats 450W Max. So you can not max out the current for all of the different voltages. It would have to be a balance of the three 12 volts current draw. Example V1 could be 18 and V2 can be 18, but V3 can only be 1.5 Amps. Or 12 + 12 + 13.5 Amps. Any combo that is less than or equal to 37.5 Amps. But also notice that if this was used in a computer you also have to balance all 3 voltages to equal less than 581.5 amps.
Clear as mud?

Thanks so much for the help.

Actually, as hard as this is to believe, I think I understand that.

Let me just make sure about something. Since I am only concerned with the 12V, the most I can get out of this power supply is 37.5 amps, which is more than I need. Is that correct?

Second Question: I'm a little confused as to what V1, V2 and V3 are. Does this mean that there are 3 different 12V connections coming out of the power supply? If so, how do I know which ones they are?

Third Question: A long time ago I looked at someone's explanation of how to use an ATX power supply and they said to combine ALL the black wires and combine ALL the yellow wires. But since there is a V1, V2 and V3, something tells me I'm not supposed to combine these........ or am I?

Bob

[Steven]

WeissWelsh wrote:

Second Question: I'm a little confused as to what V1, V2 and V3 are. Does this mean that there are 3 different 12V connections coming out of the power supply? If so, how do I know which ones they are?

The current limits specified on the label for the different 12V connections ("rails") are mainly because of the limits of the Molex connectors and the limits of the copper wire itself. Most ATX power supplies connect all 12V rails to the same place inside.

Third Question: A long time ago I looked at someone's explanation of how to use an ATX power supply and they said to combine ALL the black wires and combine ALL the yellow wires. But since there is a V1, V2 and V3, something tells me I'm not supposed to combine these........ or am I?

With the power supply turned off (and unplugged!) measure the resistance between the 12V (yellow) wires with an ohmmeter. If it's less than 10Ω, then they all go to the same place, and it's safe to combine them.

[WeissWelsh]

Steven wrote:

With the power supply turned off (and unplugged!) measure the resistance between the 12V (yellow) wires with an ohmmeter.  If it's less than 10Ω, then they all go to the same place, and it's safe to combine them.

Thanks Steven. I will do this and let you know what I find out.

Let's assume for now that they all go to the same place and that I'm allowed to combine all the yellows together and all the blacks together. When I connect these to the DC Controller, would I take half of the wires and connect them to the input of one 8-channel bank and the other half of the wires to the input of the other 8-channel bank?

I'm sorry for being so ignorant about this. :-)

Bob

[Steven]

WeissWelsh wrote:

When I connect these to the DC Controller, would I take half of the wires and connect them to the input of one 8-channel bank and the other half of the wires to the input of the other 8-channel bank?

Yes, that should distribute the current evenly enough.

[OneHotRT59]

WeissWelsh wrote:

Let me just make sure about something. Since I am only concerned with the 12V, the most I can get out of this power supply is 37.5 amps, which is more than I need. Is that correct?

Second Question: I'm a little confused as to what V1, V2 and V3 are. Does this mean that there are 3 different 12V connections coming out of the power supply? If so, how do I know which ones they are?

Third Question: A long time ago I looked at someone's explanation of how to use an ATX power supply and they said to combine ALL the black wires and combine ALL the yellow wires. But since there is a V1, V2 and V3, something tells me I'm not supposed to combine these........ or am I?

Bob

Here is a link to a video on how to make a bench supply out of an ATX power supply.
In essence, this is what you are attempting to do.

http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply

To answer one of your first questions as to how much juice your power supply will give, you must remember that the watts stated are the maximum wattage it can supply through all the rails and voltages. A 600 watt power supply draws just that if pushed to it. But, depending on the quality of the power supply, what you get out of it is much less. In your case, your power supply is about 75% efficient. So if you do the math, 51 amps * 75% = 38.25. This is probably the safe amperage you will get before you start to fry the whole power supply. On each your 12V1 and 12V2 rails, if you push past 13 amps, you will be pushing it internally. Fuses will start to pop!! Also depends on the design, as most lower priced multi rail power supplies are really one power supply split internally to protect the thin lines to the PC. Here is another link that explains some of the difference of multi-rail power supplies!!

http://www.jonnyguru.com/forums/showthread.php?t=3990

Good Luck, as I plan on doing the same thing in 2012!!

Randy

[Max-Paul]

Onehotrt59,

I am sorry but I think your mistaken. Look at the input data for that P.S. its 115V * 10A = 1150 watts. Cause of the .75 efficiency (that you called out) your still looking at over 750 watts, but they have degraded still further and call it 600 watts. I do not suggest ever running at 100% published ratings. But if he was to tie all 3 12V rails together (if this will even work? I have no experience at this) then he will have 450 watts or 37.5 amps available.

[OneHotRT59]

Thanks Max-Paul,

I stand corrected!
That's what I get for an early alarm today!!
My math was running in reverse.

I would be concerned that the power supply listed above would not withstand that kind of continuous current though. Those numbers are probably on the peak side of the curve rather than continuous. The label is sort of misleading as most pc power supply labels are less than clear.

I usually run a good Antec in my pc builds, and there are a couple of them in the 620 - 650 continuous watt arena that provide ample steady current for this application, without getting to the top of the current draw. Even these claim to be 80% efficient, and the numbers do not add up as expected. Best to use the numbers as a guide.

My final link !!

http://en.wikipedia.org/wiki/80_PLUS

This one helps decipher those label ratings.

Hope I didn't mislead anyone. The links are very helpful though!!

Randy

[Max-Paul]

Randy,

I read your finial link. Thats a Wikipedia link. First it must be reconized that those postings are suspect. But your link is to a government wanting for a standard energy efficiency.

I am not really sure what you mean that the numbers not adding up? We are in agreement that even though the label shows more amps than watts. The amps are stated as maximum per rail. But the total amps for all rails in that voltage range can not exceed the maximum wattage noted below that group of rails. That is why in the example we have on the 12 Volt rails 18, 18, & 15 amps. which equals 51 amps. And watts law says if we multiply the voltage by the amps we will get the watts. 12 * 51 = 612 watts. Which happens to be over the max limit of 5XX (cant remember actual number. So, actually you cant pull the full max current rating for each rail. Now I am calling a rail what the label calls example 12V1 or 12V2 or 12V3.