My Dimmable T5HO Hood

[Salmon McCloud]

I'm having trouble with my internet so no progress on the pics. Sorry, tomorrow I'm going to a friends place, I will take my laptop over there. Also. I'm going to take the ballast under a magnifying glass see if I can get some numbers on the ICs

Sent from my ADR6300 using Tapatalk

[Salmon McCloud]

Okay this is what I got... pictures taken by camera on my phone lol

These are the Lutron ECO-T524-120-1

ballasts side by side.
http://i1140.photobucket.com/albums/...d/IMAG0246.jpg

ballast opened up
http://i1140.photobucket.com/albums/...d/IMAG0247.jpg

The only ICs I could read were the 4862 and the IR2111
http://www.alldatasheet.com/datashee...N/TDA4862.html
http://www.datasheetcatalog.com/data...1/IR2111.shtml

The others on the vertical board in the middle were hard to read without moving the capacitors. I was able to read one. the 2842 IC.
http://www.alldatasheet.com/datashee...6/KR/2842.html

and the LM224 (2 of these)
http://www.datasheetcatalog.com/data.../2/LM224.shtml

The other 2 have a 239 and EZ DL 633, but I can't find anything on these.

And thats all I have so far.

[DarkCobra]

Interesting. More complex than I expected.

A PFC IC, like the TDA4862 or similar, was expected.

The 2842 isn't the bandpass filter you linked. It's almost certainly a current-mode PWM controller. This is a common chip in various power supplies. A bit surprising to see it as the heart of this ballast, instead of a more specialized IC.

The IR2111 is a half-bridge driver, which would be needed to interface a 2842 to the output MOSFETs.

And finally, eight op-amps in the 2x LM224's. The remaining unidentified chips may just play minor roles.

Thanks for the info. I was curious.

[Aquaticus]

So these ballasts are really cheap on eBay now, but I am struggling with how to control the dimmer. I like the idea of X10, but it's just another thing to get into. My soldering iron hasn't seen much action since college, but it would be cool to have a microcomputer controller that you could set and walk away from, since once you set the program, you probably aren't going to be making changes very often. I'm sort of surprised that someone hasn't done it already, but I haven't been able to find anything yet.

The ballasts are cheap enough (at least the two 39w ones), that I'll probably order a couple just to have around. I can always run it as a normal ballast until I find some time to figure out a way to get the dimmer function that I want, be it X10 or another solution.

[Aquaticus]

What is the distance between your bulbs?

Also, did you use 1x6 stock? Why?

Thanks!

[DarkCobra]

Super easy to connect and dim these Lutron ECO-series ballasts, like the one I used and the one you PM'ed me about on Ebay. You use only the set of three terminals, colored white-orange-black on the left side.

Connect white to the neutral line of the AC plug. Connect black to the hot line of the AC plug. You can install a DPDT switch between the AC plug and these two terminals, if you want the fixture to have its own on/off switch; but as most people will be running off a timer, it isn't necessary.

Connect a standard wall dimmer between hot and the orange terminal. Connect a suitable resistor (as described in the original post), or even one of those little plug-in incandescent nightlights, between orange and neutral. Apart from wiring up the bulb sockets (make sure you get unbridged sockets), for which there's a handy diagram right on the ballast, you're done.

Note that turning off the dimmer won't completely turn off the ballast, only bring it down to 10%. You have to cut the power to the black terminal for complete turn off.

[DarkCobra]

Originally Posted by Aquaticus

What is the distance between your bulbs?

Velcro adjustable, currently at about 6".

Originally Posted by Aquaticus

Also, did you use 1x6 stock? Why?

I think it was 1x6 for the sides, and 1x10 for the top.

I wanted the exterior to be as clean, seamless, and simple as possible, with the only exception being the finish. No exposed plywood edges, or veneers to cover them up. No visible hardware or fasteners except on the top. Rounded edges. And I have limited skills and tools. Solid wood seemed the easiest choice. It's a bit heavy, but suspended by the spring tensioners, it's almost weightless above the tank.

You can use anything you want. This isn't meant to be a woodworking tutorial, those details really only serve as an example to show that even a mostly clueless person can make something nice.

[Aquaticus]

Thanks! I love the way it looks, but I was wondering if 1x4s would be too thin? 3.5" inches should fit the bulb, reflector, and ballast fine, I would think. Thoughts?

[DarkCobra]

Yes, 3.5" is room enough.

But if you join the top and sides as I did, you lose another 0.75", so only 2.75" remains. A recessed splash guard shaves off a little more space. Not mounting the ballast directly on the wood so the back of the case can get airflow, a little more space if the ballast doesn't fit between the reflectors. And so on. If you plan out everything carefully, you can probably make it work.

Being the first time I did this, I didn't entirely trust my plan. I also thought I might add a third bulb and another ballast in the future, if I wanted to experiment with high intensity bursts; though that never happened. And should something happen like the ballast fails or reflectors corrode, the replacements might be larger. So I just opted for the 1x6, and no worries about space at all.