DIY SMD LED Pendant Light - The Planted Tank Forum
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 253 (permalink) Old 02-04-2014, 01:25 AM Thread Starter
Planted Tank Guru
 
Hoppy's Avatar
 
Join Date: Dec 2005
Location: Sacramento, CA
Posts: 20,928
DIY SMD LED Pendant Light

I failed to make a usable light for my tank from high wattage LEDs, so now I'm trying to make one from low wattage SMD LEDs, supplied as self adhesive tapes. I have ordered the LEDS, at least the white ones, from Ebay, and have purchased the aluminum for the heatsink from my local surplus metals dealer, and have started to build the heatsink. Here is the design: (showing a cross section.)



Notice that my LED light calculator program indicates that this will work very well, but that program isn't based on the SMD LEDs, so the result may vary considerably from the calculation. Much more to follow.

Hoppy
Hoppy is offline  
Sponsored Links
Advertisement
 
post #2 of 253 (permalink) Old 02-04-2014, 01:40 AM
Planted Tank Obsessed
 
Salmon McCloud's Avatar
 
Join Date: Aug 2011
Location: Dayton, Ohio
Posts: 428
Are heatsinks even necessary?

Sent from my galaxy note 2

Salmon McCloud is offline  
post #3 of 253 (permalink) Old 02-04-2014, 03:45 AM Thread Starter
Planted Tank Guru
 
Hoppy's Avatar
 
Join Date: Dec 2005
Location: Sacramento, CA
Posts: 20,928
All LEDs generate heat because none of them are 100% efficient. A single LED may not need a heat sink to dissipate the heat, but when you put 10 tapes of LEDs side by side, where the LEDs are spaced 2/3 of an inch apart, it would be foolish to assume that no heatsink is needed. These LEDs together will use about 80 watts, so there will be considerable heat involved.

I found the red and green LED tapes for $10 each, but I also got a dimmer for them at $4, so I saved a little.

Hoppy

Last edited by Hoppy; 02-04-2014 at 03:50 AM. Reason: More info
Hoppy is offline  
post #4 of 253 (permalink) Old 02-04-2014, 04:35 AM
Algae Grower
 
Join Date: Aug 2012
Location: rushville, indiana
Posts: 85
go for it!

i thought you were doing pendants??? did you tell in your pendant log what happened...if not pm me and let me know cause I am building some pendants for my system. I will follow this build for sure..
doc
drhemlock2 is offline  
post #5 of 253 (permalink) Old 02-04-2014, 04:44 AM
Planted Member
 
Greystoke's Avatar
 
Join Date: Jul 2010
Location: Port Elizabeth, South Africa
Posts: 239
@ 80Watt total, there may be merit in using a perforated board (with " holes ?), or even a metal grate as the top of the box.

Regards
Cor
Greystoke is offline  
post #6 of 253 (permalink) Old 02-04-2014, 06:06 AM
Algae Grower
 
Join Date: Nov 2011
Location: Alberta, Canada
Posts: 129
Why not just use crees from the start? They are fairly cheap on fastTech. http://www.fasttech.com/category/160...s/MTMyPUNyZWU/
Deano85 is offline  
post #7 of 253 (permalink) Old 02-04-2014, 07:23 AM
Newbie
 
thelub's Avatar
 
Join Date: Jan 2013
Location: SE Washington
Posts: 1,983
I thought your pendants were doing good? I just went back and didn't see why you think they failed. Did I not go back far enough?

Do you think any of these options would be good enough for a 28" deep aquarium? I'm still trying to decide how I want to light it and still be cost effective. Or does 28" depth and affordable not coincide with eachother?
thelub is offline  
post #8 of 253 (permalink) Old 02-04-2014, 04:04 PM Thread Starter
Planted Tank Guru
 
Hoppy's Avatar
 
Join Date: Dec 2005
Location: Sacramento, CA
Posts: 20,928
This will be a pendant, hanging about 36 inches from the substrate, 12 inches above the top of the tank. The 4" diameter, 30 watt pendant I tried did not produce enough PAR at the 36 inch distance, so I dropped the project and sold the parts on the For Sale forum.

The SMD tape will provide about 300 LEDs, for about $15! These are 30 lumen LEDs, not the tiny output ones the original LED tape used. I chose them because I want to try them, they are cheap - very cheap - and my PAR calculation program says they will work. Also, they don't need a LED driver - each LED has a current limiting resistor build in.

Also, I have noted that Finnex LED lights use SMD LEDs, so it is certainly possible to generate high PAR with them.

Hoppy
Hoppy is offline  
post #9 of 253 (permalink) Old 02-04-2014, 06:22 PM
Newbie
 
thelub's Avatar
 
Join Date: Jan 2013
Location: SE Washington
Posts: 1,983
Nice. I'll be tagging along on this one for sure.

Have you ever played around with the GU10 LED bulbs at all?
thelub is offline  
post #10 of 253 (permalink) Old 02-05-2014, 12:40 AM Thread Starter
Planted Tank Guru
 
Hoppy's Avatar
 
Join Date: Dec 2005
Location: Sacramento, CA
Posts: 20,928
Quote:
Originally Posted by thelub View Post
Nice. I'll be tagging along on this one for sure.

Have you ever played around with the GU10 LED bulbs at all?
No, I looked at those bulbs and decided they wouldn't do what I want, but I don't recall the details. Two reasons the tape mounted LEDs are so cheap are: they are produced as printed circuits, and they are apparently widely used to decorate automobiles. They are also used for store decorations, and other accent room lighting. That makes for a big market, compared to star mounted LEDs, so there are many vendors competing for the business. I'm getting mine from US distributers, one located within a hundred miles from here.

Hoppy
Hoppy is offline  
post #11 of 253 (permalink) Old 02-05-2014, 01:03 AM
Algae Grower
 
Pakman's Avatar
 
Join Date: Nov 2013
Location: Bay Area, NorCal
Posts: 122
I've used a similar LED tape that was probably on the cheap side of manufaturing. It was pretty bright and easy work with, but I've since noticed that I have a few LED's burning out... probably quality control on the off-brand strips and maybe water effecting the circuit (even though it was sold as waterproof and comes encased in some sort of rubber). Since we are on the topic, was recently seeing some interesting circular panels on amazon that could be interesting... anyone look at things like:
Amazon.com: Mudder 12w 2835 SMD LED White Light Round Recessed Ceiling Panel Down Light Lamp: Home Improvement Amazon.com: Mudder 12w 2835 SMD LED White Light Round Recessed Ceiling Panel Down Light Lamp: Home Improvement
Pakman is offline  
post #12 of 253 (permalink) Old 02-05-2014, 04:22 AM
Planted Member
 
Greystoke's Avatar
 
Join Date: Jul 2010
Location: Port Elizabeth, South Africa
Posts: 239
Quote:
Originally Posted by Hoppy View Post
. . . Two reasons the tape mounted LEDs are so cheap are: they are produced as printed circuits, and they are apparently widely used to decorate automobiles. They are also used for store decorations, and other accent room lighting. That makes for a big market, compared to star mounted LEDs, so there are many vendors competing for the business. I'm getting mine from US distributers, one located within a hundred miles from here.
. . . and, it's an attempt to increase the commercial life of the cheap, low-power LEDs which are only half as efficient as the Cree-types. Besides, some makes suffer badly from sulfuration.

I've given-up on them . In my opinion, the best DIY LED units are made from LEDs rated greater than 1Watt/LED.

Regards
Cor
Greystoke is offline  
post #13 of 253 (permalink) Old 02-05-2014, 08:38 PM Thread Starter
Planted Tank Guru
 
Hoppy's Avatar
 
Join Date: Dec 2005
Location: Sacramento, CA
Posts: 20,928
Here is the mechanical part of the light - a heatsink made from 4 strips of 1/8" x 1 1/2" aluminum.





This is assembled by drilling and tapping holes in the pieces and using #6-32 screws to hold it together, with 4 #8-32 eyebolts for hanging it.

Hoppy
Hoppy is offline  
post #14 of 253 (permalink) Old 02-05-2014, 08:42 PM Thread Starter
Planted Tank Guru
 
Hoppy's Avatar
 
Join Date: Dec 2005
Location: Sacramento, CA
Posts: 20,928
Quote:
Originally Posted by Greystoke View Post
. . . and, it's an attempt to increase the commercial life of the cheap, low-power LEDs which are only half as efficient as the Cree-types. Besides, some makes suffer badly from sulfuration.

I've given-up on them . In my opinion, the best DIY LED units are made from LEDs rated greater than 1Watt/LED.
They are cheap enough to experiment with, but I may end up giving up on them too. If the light works for 3 years I will be delighted, since I will want to try something else by then anyway. And, it isn't necessary to make the best DIY LED light, just one that meets our needs.

Hoppy
Hoppy is offline  
post #15 of 253 (permalink) Old 02-06-2014, 05:29 AM
Planted Member
 
Greystoke's Avatar
 
Join Date: Jul 2010
Location: Port Elizabeth, South Africa
Posts: 239
Quote:
Originally Posted by Hoppy View Post
. . . And, it isn't necessary to make the best DIY LED light, just one that meets our needs.
True
(although in my opinion: "best" really means "fit for purpose")

Regards
Cor
Greystoke is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the The Planted Tank Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome