DIY LED driver for reef lighting

Lightbulb!!! Thanks fishman and taqpol for clearing that up. I only got as far as one class of ece in college so im a complete beginner with all this stuff. Reading all these led threads has just made me jump into the hobby again. Starting small though: a small 17 gallon. I don't want to deal with moving a huge tank.

Sidenote: I just received the cat4101 chips today. WOW that's going to take some fine soldering skills... Which I have yet to develop. Haha I'll keep in touch and or start a new thread for my build. Thanks again for all the help!
 
Last edited:
I haven't taken ANY EE courses, so don't shortchange yourself! :)

Moral of the story, Meanwell makes many, many different products. Unfortunately, here in the Reefkeeping world, when you say "Meanwell" people automatically assume you mean an ELN 60 48 LED driver.

Soldering the CAT4101 is not hard at all once you get the hang. Page through this thread, we've discussed typical approaches a few times. I find that once most people get the hang of SMT they like it better than through-hole (I do, at least).
 
Thanks DWZM!

Im on the sra site and im choosing supplies. I just wanted to make sure these supplies were good to use:

- Aoyue 937+ DWZM recomeneded =]
- Solder Iron Tip T-2C bevel style more for soldering the wires and stars
- Wire 63/37 Rosin Core .032 (couldnt find 60/40 kester 44 on the site so i think this is a comparible soldering wire)

Optionals:

- Third Hand with Tweezers
- Double Clamp Stand with Magnifier

Looking at the size of the CAT4101 and the other components that are even smaller i was thinking that the optional tools would be pretty helpful... or should i just pick up some of that blue poster putty? Input on all the selections?

Thanks!
 
Obviously I like that iron, so it gets a thumbsup. I haven't tried that specific tip, but as long as it's squat and not super-fine it should be good. The solder you picked looks Ok.

As far as the optional tools - it'll depend a bit on your technique and your personal preference. I know some people that use a small vice to hold the PCB up off the table, and some people that like the "third hand" or other such tools. I don't use any of these. I put the PCB flat on a table and hold parts with hand tools - super fine tweezers, a dental pick, and/or blue-tack.
 
Thanks again DWZM!

The only soldering I've done is car wiring so I can't really say I even have a technique for PCB's yet. I think I'll try the blue tack method and see what technique forms from there. The boards will be here in 2-3 weeks so I can think about it then. The tank and stand come in this Friday though so the plumbing and acrylic work should keep me somewhat occupied.

Thanks again!
 
Last edited:
I just got the other compotents for the board yesterday evening... o_O

Yeah.. blue tack and tiny tweezers it is! Now im just waiting on the actual pcb's.

This should be fun =]
 
Is a 45 watt soldering iron enough? One of the popular vendors of LED's recommended a 100watt soldering gun, as that is what they use for building the systems they sell online.
 
Those are called linear controllers. Any power not sent to the LEDs has to come off the CATs... They can only take about a Watt. You need to tell us the Vf of the string you're driving and the voltage of the DC supply you're running it all with. It would be very helpful to know the current you're ending up with too.
 
nreefer said:
Is a 45 watt soldering iron enough? One of the popular vendors of LED's recommended a 100watt soldering gun, as that is what they use for building the systems they sell online.
Click to expand...

45 should be enough if you have a clue about soldering. The 100W would certainly be faster and better on the LEDs but is not as utilitarian. Like you wouldn't use it for soldering electronics.
 
seti,

In addition to kcress's comments, I would try very hard to check for faults or shorts on the board or your soldering work. The situation you're describing is not typical operating behavior. Also, can you tell us what circuit you're using? You mention a wall wart and a pot, how exactly are those wired?
 
seti007 said:
Hi all, I am having some issues with my build. I have the tripple cat board assembled and to test it out, I have 6 of Steve's dual emitter LEDs connected to one of the CATs in series. Well, after applying a 5v signal to PWM it turns on and everthhing but within 5 minutes or so, the CATs overheat so horribly that one time they even smoked a bit. It still functions after I turned it off and let it cool. The Walwart supplying the 5v tends to overheat as well and turning the variable resistor (10K pot) at RSET has absolutely no effect on the intensity of the light ( I have it in series with a 680 Ohm resistor). The only thing that seems to cahnge the intensity is if I vary the 5v input. I wonder if there is a short on the board or what? Can each one of the CAT's drive 6 of these LEDS? Im driving the whole thing with a 24V 2.5A power supply.
TIA

EDIT: I let it run longer ~10 mins and it actually melted the solder behind the CAT4101 chip. Thats Damn hot !!! Something is obviously wrong and Im hoping that it may be something as simple as the number of leds Im driving.
Click to expand...

If your power supply is adjustable, you need to turn down the voltage. I have a couple of the cheapo POTrans power supplies, they have an adjustment, and I turned them down to just above 20v. In general you need .5 above the Vf of the LED string, but the guys here recommend giving it a little more, like .6 or .7 above. So if you are dropping 19.2v on your LED string, you would set the power supply to around 19.9v. Before I turned down the voltage, they got hot.

I also put small heatsinks on my CAT4101s (using Arctic Alumina adhesive)
 
I just looked at one of Steve's LED the Vf is 3.8-4 so he is in the right range with 24 volts. Since you says dual emitter I wonder how you have them wired. Do you have 2 string of 6 or six strings of 2. I expect the second so you only are dropping 7.6 - 8 volts across the LEDs and the rest (about 16) on the CAT. If so I can see it getting hot very fast.
 
Fishman, Steve's "dual emitter" LEDs are simply two emitters on the same die, in parallel. For all intents and purposes, it acts like a "single" LED from an implementation point. The "dual" part takes place inside the chip and isn't apparent when wiring or running the LEDs.
 
Thanks DWZM, I didn't think to look that up while I was there. But the description still sounds like he might have wired them in parallel rather than series. Just a thought to check.
 
Hi!

If anyone have spare CAT4101 driver pcb's for sale, please PM me. I place an order with itead several weeks ago but apparently it got lost in the holiday rush.

Regards!
 
I still don't think the behavior you're seeing is typical. When you "overload" a CAT4101 by trying to get it to drop too many volts, the overload protections in the chip kick in and shut it down WAY before you get to the point where the solder melts or anything smokes. Also, regardless of it you're overdriving it or not, adjusting a pot between RSET and GND will affect the drive current in an obvious manner. I strongly suspect that either you have a fault on your PCB or the particular CAT4101 chip you're using is damaged or faulty - You may ALSO be overdriving it, but I don't think that's the only thing going on at this point.
 
You must log in or register to reply here.

Similar threads

C
DIY Stand for Flatback Hexagon Tank
Replies
2
Views
763
Drummer98
Drummer98
T
Looking for a specific tank build - EZTube.com sent me here
Replies
6
Views
537
Reefing102
Reefing102
Emanuel92
What lighting for S. haddoni and E. quadricolor?
2
Replies
20
Views
1K
Hong Kong
Hong Kong
C
Scored a complete setup for $100
Replies
13
Views
1K
griss
griss
R
Red tufty algae - Asparagopsis - any expert advice for removal?
Replies
14
Views
2K
rallibon
R
Back
Top