Questions about diy led's/drivers.

[cedwards04]

I am fairly handy and like building things, so I have decided to build a diy led light fixture. I am trying to research everything before buying anything so that I have a good knowledge base to start. This will be a budget build, and I have located a source for very inexpensive individual led 3w bulbs. My confusion comes in with the drivers. I simply have not been able to wrap my head around how to determine what driver I need to power the leds.

I remember quite a few years back I had done a lot of research on the matter and rapid led had a fantastic explanation on their website, but I have forgotten what I read, and that information is no longer on their site.

I want something that is dimmable, not so much for programming, but so that I can dial in the different colors until I get the look I want. Any help would be appreciated. I plan to do this first one with very cheap parts, mostly has experimentation. If I am successful I will build a higher quality version once I upgrade the tank.

 

[NanoReefWanabe]

Many different ways to go about this...

You going to use a controller ie apex reefkeeper arduino?
Depending how you plan to dim the leds you can use different drivers.

I am using the Lumina fixtures that have five channels built into them in a COB fixture...

I am using meanwell power supplies and ldd drivers.

You need too know the amperage and forward voltage of your leds to determine what you need for power supplies and drivers...

 

[cedwards04]

3.2-3.4v, 700ma. That sound about right? I will be dimming using cheap potentiometers, like I said, this is a super low budget experimental build for a 20 gal tank. Nothing fancy at all.

 

[mcgyvr]

For series strings..
The current rating of the driver should match the rating of the LED.. So if 700mA then the current rating is 700mA..
The dc output voltage rating must be greater than the sum of the Vf (forward voltage) of the leds

So with 10 x 3V @700mA LEDs in series you need a driver with a DC output voltage greater than 30V and a current rating of 700mA
Then pick one that can be dimmed via potentiometer (resistor with a hand knob) like the Meanwell LPF series..

 

[mcgyvr]

I remember quite a few years back I had done a lot of research on the matter and rapid led had a fantastic explanation on their website, but I have forgotten what I read, and that information is no longer on their site.

oh and one of the wonderful things (and bad things if they get your nude pictures :lmao: ) is that the internet never goes away..
if you forgot what you read.. simply find it again and reread it..
https://www.rapidled.com/led-university-1/

 

[cedwards04]

oh and one of the wonderful things (and bad things if they get your nude pictures :lmao: ) is that the internet never goes away..
if you forgot what you read.. simply find it again and reread it..
https://www.rapidled.com/led-university-1/

Like I said before, that is not the same information that was there years ago when I read through it. And i didn't quite understand what they were saying now.

 

[cedwards04]

For series strings..
The current rating of the driver should match the rating of the LED.. So if 700mA then the current rating is 700mA..
The dc output voltage rating must be greater than the sum of the Vf (forward voltage) of the leds

So with 10 x 3V @700mA LEDs in series you need a driver with a DC output voltage greater than 30V and a current rating of 700mA
Then pick one that can be dimmed via potentiometer (resistor with a hand knob) like the Meanwell LPF series..

This clears things up for me perfectly. That's exactly the info I needed to confirm. For some reason I had a very hard time finding that explained so simply online. Thank you.

 

[cedwards04]

One other quick question. Would it be ok to use a programmable driver that is capable of going over 700ma as long as I keep it turned below that? Specifically I am talking about this driver https://www.1000bulbs.com/product/177277/LEDF-AC25CD125APMV.html

If I am reading it correctly, I can wire this directly to my 110v ac wall outlet, and use this to run a string of leds. It appears to be programmable via a phone app and ill just make sure I do not exceed 700ma. Does this sound correct? I would buy one of these per channel, it seems that one will be big enough to run all my same colors, so I can control each color output individually.

 

[perkint]

The spec sheet for that driver seems to suggest the output current is controllable, so it should be OK. A lot of controllable constant current drivers don't actually vary their output current (just use PWM to control how much of the time they are on for, which controls brightness).

Just to add as I don't think it has been mentioned. It's not a bad idea to under drive LEDs (eg one that is rated for 700mA gets run on 500mA) as this can help with longevity and also reduce heat production and usually doesn't reduce the light output as much as you'd think.

Personally I'd use a single PSU and then mean well LDDs for drivers. Add an arduino for brightness control. Yes, it means coding and something like the Uno/nano can only control 6 channels, but they are a pittance to buy and are very easy to expand if you wish to do full sunrise/sunset, etc And the coding would only be a handful of lines (you could even use 'pots still).

Tim

 

[mcgyvr]

One other quick question. Would it be ok to use a programmable driver that is capable of going over 700ma as long as I keep it turned below that? Specifically I am talking about this driver https://www.1000bulbs.com/product/177277/LEDF-AC25CD125APMV.html

If I am reading it correctly, I can wire this directly to my 110v ac wall outlet, and use this to run a string of leds. It appears to be programmable via a phone app and ill just make sure I do not exceed 700ma. Does this sound correct? I would buy one of these per channel, it seems that one will be big enough to run all my same colors, so I can control each color output individually.

I am not familiar with it.. Quick glance...It seems there is some "wand" that needs to be purchased to program it.. (or ok.. a phone with NFC)..
BUT.. I would just purchase a meanwell LPF as I stated above..
Its proven/does exactly what you need/doesn't require programming,and should be right about the same price (far less if you need to purchase a wand too).. Oh and the one you show is only analog 0-10V dimming so you would need a controller or to construct an adjustable power supply..

Just go meanwell.. It too plugs right into 110vAC and then you just need a 100k potentiometer for dimming as you wanted.. But can easily change to PWM or analog dimming if you upgrade..
meanwell is better..

 

[d0ughb0y]

if your objective is budget, then I think you can actually get a ready made fixture (new or used) for less, and it won't look as ugly as a diy.
if your objective is learning, then go for it.
a few years back, diy was a feasible option, hence several diy led sellers started popping out during that time.

 

[mcgyvr]

and it won't look as ugly as a diy.

All relative..

 

[lingwendil]

All relative..

There are some very nice enclosures available...

 

[d0ughb0y]

I do a lot of diy, and sure you can make anything nice, but by the time you add up all the costs, it would be close or (more likely) even exceed the cost had you just bought one. A lot of the costs are hidden.

so like if you buy the nano kit plus the nice enclosure, I'm sure you can get a used radion or hydra for less $ and more importantly, less headache.

 

[d0ughb0y]

Case in point, this kit

You can get a brand new hydra26 HD for $350, or used one for $250.

 

[lingwendil]

You can build a much nicer light than that kit for half the money, so it's a poor example...

 

[d0ughb0y]

nicer than a radion hardware and software?
just writing software from scratch alone will require some skill. its not an easy job if you want it refined and professional looking.
sure you can make a really bare bones light, with no software for less and wait a month for parts from china, etc. but its not going much less then say a $250 used hydra hd. not worth all the hassles and headaches. few years ago it is definitely feasible to diy. times change.

it is also convenient to not disclose the hidden costs to make it look cheaper.

there are legitimate reasons to diy, but cost saving is not one of them.

 

[d0ughb0y]

I encourage diy. as we need more makers in the hobby.
just that the op said the constraint is budget.

 

[oreo57]

Case in point, this kit

You can get a brand new hydra26 HD for $350, or used one for $250.

kind of unfair when you throw in a full Bluefish..
Using a Storm and it's only $280.....

Oh and try to fix a Hydra when a diode fails..

Or replace a "color" when someone finds pink increases biomass..

On eek bay you can get Luxeon Rebel stars for $1 each..
Avoiding "Bridgelux" types ( 10/ for practically nothing) and fake CREEs................


now I'm still on your side.. It is getting harder to DIY for substantially cheaper than buying retail.. BUT..that is really only due to the fact that DIY is helping drive down the price and chip manuf are driving down the price of diodes..

cheating w/ solderless isn't helpful either..
like the markup and hidden cost of "expensive" connectors..

IF you go man. dimming It is easy to build it for $100...
I'll even pad this a bit.

24 Luxeons $30
2 LDD=HW's $14
TWO 48V power supplies.. just because .
$12 each.

2 Manual PWM dimmers $ 10
12"x12" heat sink (overkill)
$60
http://www.heatsinkusa.com/12-000-wide-extruded-aluminum-heatsink-low-stock-please-call/
This can go as low as free..
Wire... please not like it can't be scavenged for the most part.
but 100ft 20ga zipcord $11
https://www.ebay.com/itm/Audiopipe-...531567&hash=item235d31961a:g:RDAAAOSwi1ZZd5CO

Heatsink plaster $0.99 5g

Of course one always needs tolls but that is more of a given when one starts these things..


Well $139.99 but mostly due to the overly expensive heat sink..

$89.99 w/ out it..

move up to a modified TC-420 for basic ramp up/down of 5 channels 4A each..Add $30

Point is selective shopping..

 

[d0ughb0y]

I added the bluefish to actually make the comparison to hydra 26 hd a little bit fair, to have some form of wireless control. I'm not familiar with the bluefish software if it can adjust leds based on color temperature and provide power usage info.

Writing a well polished software will significantly add more time and cost to the diy unless someone has already done so and offer it as freeware.