Has anyone used these DC-DC converters?

[plasmadrive]

I ordered about 60 of these and since they are late in arriving I thought I would start some research on them on using them.

 

http://www.aliexpress.com/store/product/LM2596-DC-DC-adjustable-step-down-power-Supply-module-DC4-35V-input-1-25-30V-output/701799_825132631.html

 

Turns out that from what I have found out there on the web, I may not have done the smartest thing in the world.  Not sure they are the very same modules, but if they are, the fail rate according to what I found seems to be very high.  Also it appears to many that the chips used are NOT the real deal.  Not saying that is the case here.. just saying that is the info I found with very little search time. 

 

So, has anyone had any experience with these specific ones from Ray?  If so, care to share? 

 

I am specifically worried about failure do to heat and the internal thermal shut down not working.

 

 

[scubado]

What are you hoping to use them for?  I just use resistors, a whole lot cheaper.

 

http://home.cogeco.ca/~rpaisley4/LEDcalc.html

 

http://ledz.com/?p=zz.led.resistor.calculator

[plasmadrive]

Jim, what I want to use them for requires 5vdc.  Can't just use resistors for distributed power on 2812B.  

 

My question was if anyone had actually used them before.  I am looking for some real hands on feedback regarding that very specific converter from Ray.. 

 

The stuff I dug up on the web after I ordered them got me a bit worried.  I should have looked all that up first... but I didn't.. I got in a hurry.. hopefully not to my peril on the display. We shall see! 

[Orville]

Why even use a converter at all?   If I need 5VDC on something, I just use a 5VDC regulator found at most local Radio Shack stores.  I can put 120VAC in and get 5VDC out, use these in my G Gauge Locomotives and Lighted Passenger Cars and any Lighted Caboose when I switch out the incandescent bulbs for L.E.D.'s.    So don't know why one wouldn't just use a 5VDC voltage regulator.  I also use a full wave diode bridge to keep the polarity correct on DC items in front of the voltage regulator.  Very minimal parts to acquire 5VDC for almost any project requiring such low voltage.

[plasmadrive]

Oroville,

 

OK... I need regulated 5vdc @ about 3 amps for each of 60 intersections.  These will all be outside and fed with some DC buss voltage yet to be determined (12-24v). DC-DC switching regulators are the best way to do this if they are ones that are reliable.  Linear regulators produce far too much heat.  I also bought the DC converters for less then the price of a 7805 (which is only good for 1 amp) and two caps. 

 

As for what you are saying that you can put 120vac in and get 5vdc out, I assume you are talking wall warts.. or a line in switching regulator.  Not happening for <$2 each me thinks.. especially with regulation and for sure not at Radio Shack  

 

I do appriciate the suggestions, honest I do.. But what I really want to know is if anyone has used Ray's converters that I listed.  I have them on the way here and need to know if I should use them or sell them upon arrivel.  If they somene knows thru experience that they fail a lot, I don't want to use them of course,  and I will use my backup plan.  If they are stable and reliable, I will stick with this plan. 

 

Thanks

Edited August 31, 2013 by plasmadrive

[Orville]

Nope, no wall-warts, I have fed 120VAC into a diode bridge, then directly into the 7805 from that if I wanted to maintain the correct polarity, if polarity isn't an issue because the item I'm using already had that protection built in, I have fed 120VAC voltage directly into a 7805, of course the 7805 is heat sinked because they do generate a lot of heat.    If I use a wall wart, I wouldn't need the 7805 because I'd just buy the appropriate voltage wall wart with the appropriate amp rating.   See no reason for external circuitry when using a wall wart at the correct voltage and amps.

 

Okay, understand why you're looking for DC-DC converters, however, and I have no experience with the ones Ray sells, cheap ones are usually unrealiable.    Remember, as the old saying goes, you get what you pay for.   Sometimes cheaper isn't better.

 

I wish you luck with those converters and hopefully someone here has used them and can give you advice and their experience with them.

[plasmadrive]

Oroville,

 

You fed 120vac with and without a rect to a 7805????   I don't think so... not if they survived.  Those will pop at around 40v-45v.. They don't really like anything above 35vdc... and they will only take DC.  AC will blow them apart in a heart beat.  You must be thinking of a different part number and not the LM7805. 

 

As for your advise.. "cheaper isn't better".......  You may just have hit the nail on the head.   We shall see how it goes.  Theoretically they should be fine.. but from China.... well..... fingers crossed.. Ray has always been a trusted supplier, though slow to respond at times.. but alway honest.  I hope these turn out to be ok. 

[Frank Farmer]

Plasmadrive,

As soon as I saw what you had ordered, I knew exactly what you were planning on doing with them.  I had considered it myself as I'm running over 200 ft of ribbon strips across my building.  At that time I thought I was going to control everything with one big power supply and 1 controller.

I changed my plan and went with 3 smaller controllers (sandevice E6804) and power supplies (30A 12VDC) spread out over the building.  The controllers will control more channels than I'm using, but that gives me room for expansion later. I still need power injection, but I do that by running a larger guage wire from the closest power suppies to the far end ribbons. I can power/control up to 6 ribbons using one power supply and only use 1/2 the controller.

    ribbon><injector><ribbon ribbon<PS/controller>ribbon ribbon>injector<ribbon

 

Let me know how your DC/DC convertors work out.

Frank

Edited August 31, 2013 by Frank Farmer

[scubado]

Why not use a good computer power supply?  The 5V line has plenty of current.

[Ken Benedict]

I ordered about 60 of these and since they are late in arriving I thought I would start some research on them on using them.

 

http://www.aliexpress.com/store/product/LM2596-DC-DC-adjustable-step-down-power-Supply-module-DC4-35V-input-1-25-30V-output/701799_825132631.html

 

Turns out that from what I have found out there on the web, I may not have done the smartest thing in the world.  Not sure they are the very same modules, but if they are, the fail rate according to what I found seems to be very high.  Also it appears to many that the chips used are NOT the real deal.  Not saying that is the case here.. just saying that is the info I found with very little search time. 

 

So, has anyone had any experience with these specific ones from Ray?  If so, care to share? 

 

I am specifically worried about failure do to heat and the internal thermal shut down not working.

 

I have a dozen of them (not from Ray, but the same thing) and have used a couple in projects, but only at 1 amp current draw, feeding 12vdc and they worked OK. You can also stick some heat sinks on the regulator.

 

I could have brought some to the Sacramento meeting if I knew you had those on order.

 

These converters are more expensive, but waterproof and several people besides me have used these at 24v: http://www.ebay.com/itm/Waterproof-12V-24V-5V-3A-15W-DC-Buck-Converter-Power-Inverter-For-Cars-/370884950943?pt=LH_DefaultDomain_0&hash=item565a773b9f

 

I did some voltage dropout tests and they will work just fine on a 16 gage 24vdc buss, drawing close to 3 amps each.

I have some spares of these too.

Edited September 1, 2013 by Ken Benedict

[Ken Benedict]

Here's another weatherproof model, but 5A: http://www.ebay.com/itm/A-S0-Step-Down-Voltage-Regulator-DC-12-24V-to-5V-5A-25W-Buck-Converter-Module-/281158864077?pt=LH_DefaultDomain_0&hash=item41765fcccd

 

And a waterproof 8A version, if you wanted to drive two strips: http://www.ebay.com/itm/DC-Buck-Converter-12V-24V-to-5V-8A-Step-Down-Car-Power-Supply-Waterproof-Module-/130978392733?pt=LH_DefaultDomain_0&hash=item1e7eebaa9d

 

And a 10A version http://www.ebay.com/itm/10A-50W-DC-Converter-Voltage-Step-Down-12V-24V-to-5V-Waterproof-LED-Power-Supply-/350853521272?pt=LH_DefaultDomain_0&hash=item51b07fdf78

 

And a 15A version, if you wanted to drive 5 strips: http://www.ebay.com/itm/DC-Buck-Converter-12V-24V-to-5V-15A-Step-Down-Voltage-Adapter-Car-Power-Supply-/141048948798?pt=LH_DefaultDomain_0&hash=item20d72c283e

 

And a 20A version: http://www.ebay.com/itm/DC-12V-24V-to-5V-20A-100W-DC-DC-Step-Down-Power-Converter-Regulator-/121116082153?pt=LH_DefaultDomain_0&hash=item1c3314bfe9

 

And a 30A version: http://www.ebay.com/itm/DC-DC-Converter-Regulator-12V-24V-down-to-5V-30A-150W-/120764296826?pt=LH_DefaultDomain_0&hash=item1c1e1cee7a

 

And a 3A version with adjustable output: http://www.ebay.com/itm/DC-DC-12V-to-5V-24V-to-5V-24v-to-12v-Adjustable-Power-Supply-Converter-Module-/261143055474?pt=LH_DefaultDomain_0&hash=item3ccd56cc72

 

Here's the cheapest 3A, 12v ($2.57) that I could find: http://www.ebay.com/itm/V1NF-23mm-Car-Charger-DC-Voltage-Regulator-Converter-Module-12V-To-5V-3A-15W-/221268709868?pt=BI_Circuit_Breakers_Transformers&hash=item3384a491ec

 

And the cheapest 5A, 24v ($8.00) that I could find: http://www.ebay.com/itm/V1NF-Step-Down-Voltage-Regulator-DC-12-24V-to-5V-5A-25W-Buck-Converter-Module-/221271559747?pt=LH_DefaultDomain_0&hash=item3384d00e43

 

 

And if you want a DIY solution:

 

3A regulators: http://www.ebay.com/itm/LM323K-LM323-Voltage-Regulator-5V-3A-SGS-THOMSON-/140565894279?pt=LH_DefaultDomain_0&hash=item20ba615487

 

and: http://www.ebay.com/itm/20pcs-LM2576T-5-0-LM2576T-5V-3A-REG-BUCK-Voltage-Regulator-NS-/390645382531?pt=LH_DefaultDomain_0&hash=item5af4477d83

 

5A regulators: http://www.ebay.com/itm/10pcs-New-LM1084-LM1084IT-5-0-Voltage-Regulator-5V-5A-TO-220-/280952879925?pt=LH_DefaultDomain_0&hash=item416a18bb35

Edited September 1, 2013 by Ken Benedict

[plasmadrive]

Ken,

 

I wish I had done my research prior to ordering from Ray.  I had some other things to order.  His should work, but they need a lot of heatsink.  Those little peal and stick heatsinks may not be anywhere near enough.  I will have to do some testing..

 

Had I done my research I would have gone the route of the waterproof potted guys.. I still may, but I would buy them direct and not thru Ebay.. that site has become ridiculously expensive. 

 

The DIY regulators are not really an option.  Too much work and time.... they parts are also pretty expensive even from Mouser or Digikey. 

 

Thanks for all the input..  I should receive the ones from Ray here in a day or three.. I will let you know how testing goes.

[plasmadrive]

I finally got my converters today.  I have run one preliminary test.  They seem to regulate pretty well.  I did not have a load for the 5v that I wanted to trust them with so I put a 12 volt load on it and tried to take it up to two amps input.  That means something less than 2 amps out.

 

The regulation was pretty fair.  .2 volts from no load to 2 amps input.   The heat however was terrible.  The regulator chip got so hot in about 15 secondes that there was no way I could keep my finger on it.  This means heatsinking of course, but I think they just may work if I can get the heat off of them.  Now we shall see how that goes.

[Ken Benedict]

I've got some of these heat sinks coming: http://www.ebay.com/itm/New-High-Quality-5pcs-11x11x5mm-adhesive-Aluminum-Heat-Sink-For-Memory-Chip-IC-/400552779832?

 

I'm gonna try a 2A test also, when they arrive.

 

Do you have a way to glue a heat sink to yours and then to a bigger piece of metal nearby, just to spread the heat?

[plasmadrive]

Hi Ken,

 

I actually haven't figured out how I am going to enclose these yet.  I was kinda waiting to see if they would really work.  Turns out since they do work, but not without a heatsink I may just get a hunk of aluminum and a small plastic potting box and do it that way.

[plasmadrive]

Plasmadrive,

As soon as I saw what you had ordered, I knew exactly what you were planning on doing with them.  I had considered it myself as I'm running over 200 ft of ribbon strips across my building.  At that time I thought I was going to control everything with one big power supply and 1 controller.

I changed my plan and went with 3 smaller controllers (sandevice E6804) and power supplies (30A 12VDC) spread out over the building.  The controllers will control more channels than I'm using, but that gives me room for expansion later. I still need power injection, but I do that by running a larger guage wire from the closest power suppies to the far end ribbons. I can power/control up to 6 ribbons using one power supply and only use 1/2 the controller.

    ribbon><injector><ribbon ribbon<PS/controller>ribbon ribbon>injector<ribbon

 

Let me know how your DC/DC convertors work out.

Frank

Frank,

I have been doing a lot of expermenting and when I drive more then about a meter worth of the WS2811 5v strips, and I go to full white the color temp shifts past about 1.5 meter point.  I have also put about a foot of Ray's 4 core white cable with a connector on the "goes inna" and "goes outta" side of these strips.  Those are contributing to the voltage drop but I don't have any strip longer than 14 LEDs either.  So.. the bottom line is that I need to inject power every set of 3 strips which means 1 meter of LEDs for this particular prop. or 20 injection points.

 

I finally wound up ordering some 5 amp waterproof DC-DC converters from China today.  I will feed between two sets of three strips and that takes about 3 amps on white, so I should be golden.  I am used to worring about color temp shift because of my involvment with commerical LED art work.. so I am a bit picky perhaps.  Design for worst case and I won't get burned.

 

So, that means I have a bunch of the 3 amp DC-DC converters that I will not be using.. I ordered heat sinks for those as well.... sometimes I just get ahead of myself.. LOL

 

Here is what they look like

https://www.dropbox.com/sc/t5ro4uq4new4qzo/2dW2ba1uys

Edited September 5, 2013 by plasmadrive

[plasmadrive]

got my 5 amp DC-DC converters today. They look awesome.  Now to test em.  They are already potted, heatsinked and labled. 

[plasmadrive]

I got my 5 amp DC-DC converters today. They look awesome.  Now to test em.  They are already potted, heatsinked and labled. 

 

First one out of the box input test voltage 12.0vdc.  Max input current for this test 1.96amps.

• unloaded output 5.00vdc
• static test 1:  loaded @3.3amp output is 4.96vdc
• dynamically (running a show) output voltage appears between 5.00v - 4.95vdc. (meter, no scope).  Max average current during a bright passage was 4.29amps  That is the only time it dropped from 4.96v - 4.95v
• Room temp 72 deg F.  After 5 minutes at 3.3 amps constant the heasink temp has not increased that I can feel with my fingers. Still room temp.

Quick conclusion.. Awesome!  Better then I expected actually. 

 

http://www.prodctodc.com/dc-step-down-voltage-regulator-dc-1224v-to-5v5a25w-buck-converter-module-waterproof-car-power-supply-p-123.html#.UjednD-Dm2k

[plasmadrive]

I turned the voltage up to 24vdc input and have run it for one hour at 3.3 amps out.  Voltage as dropped another .01vdc.  The case temp has gone up about 6-10 degrees.  Still  below 90F.

 

I figured that I now need to run a single 24vdc 7amp supply for one building and 4 amps for the other building.  My wire size has now become very small and my voltage at the LEDs will be constant..  

 

I love toys!  

[Ken Benedict]

Glad to hear it.

 

For my test, I ran a 105% load then dropped the input voltage down gradually to find the lowest dropout voltage.

From that, I calculated the wire size and max length of the run. Ended up around 35-38 feet on 18 gage wire. (for my application).

 

Maybe you'll have the final results for this Friday's LOR meeting in Sacramento.

Edited September 17, 2013 by Ken Benedict