reefbrite repair.

PicassoDan · Aug 23, 2022

Resurrecting a super-old thread, how did this go?
I'm about to order some LEDs and drivers(?) to rebuild my 48" blue XHO.

Removing the reflector was a little tricky - it's hot-glued to the extrusion. The trick was to gently wiggle it until the hot-melt glue let go. This may have only worked because clearly my fixture over-heated. These things desparately need either active cooling fans or a better extrusion with real fins... I'm tempted to machine the back surface flat, and bolt a finned extrusion on there.

mickeysreef <*))))< · Aug 23, 2022

have all the parts, never made the repair lol

oreo54 · Aug 23, 2022

PicassoDan said:
Resurrecting a super-old thread, how did this go?
I'm about to order some LEDs and drivers(?) to rebuild my 48" blue XHO.

Removing the reflector was a little tricky - it's hot-glued to the extrusion. The trick was to gently wiggle it until the hot-melt glue let go. This may have only worked because clearly my fixture over-heated. These things desparately need either active cooling fans or a better extrusion with real fins... I'm tempted to machine the back surface flat, and bolt a finned extrusion on there.

That's one burned out driver there..
Orig design looks like a constant current 350mA driver for every six diodes. Pretty normal
A 24V constant voltage power supply.

Does the ps still work?
As a DIY guy I can see your "passion" on rebuilding but that is a pretty shot light..this isn't an antique car

For $50 you can have a 9watt /ft wide angle 453nm (maybe) reef bar .. That 36W 4ft is a bit flexible since the lights are constant voltage driven w/ resistors.

ReefBar 453 nm Deep Actinic Blue Aquarium LED Light 9W/Ft Coral Lunar Moon reef saltwater salt water

ReefBar 453 nm Deep Actinic Blue Aquarium LED Light 9W/Ft Coral Lunar Moon

21ledusa.com

Reefbrights biggest advantage is the wider spread over the "normal" 90 degree light bars.
If you are using them for "pop" even if they have 2 different "blues" it isn't that big of a difference.. in pop.
Besides once you go flea bay for the diodes it's a crap shoot as to what you get nm wise and quality.
Once you go more "respected" sources..

BUT is the one you are trying to replace a 50/50 (W/B)?
But is that what you are going to re-build it at?
Sadly the cheap bars go 2:1 1200k/blue,
https://21ledusa.com/products/2-1-12k-white-blue-reefbar-aquarium-led-light-9w-ft

To be honest, I actually trust the quality of those little 1/2w chips over the Bridgelux "egg" diodes.
I have no proof though the egg style has been notoriously low in efficiency.

By the time you get the diodes, new drovers, shrink wrap for said drivers, rebuild the heatsink, thermal adhesive, shipping and incidentals (still wondering about the power supply) you will be about at the cost of a cheap new bar 36W bar. A guess though.
At least the cheap bar you can add a dimmer to..

Oh and a 4' Quanta meso blue is $120 if you want to up the quality..or pick a different "color"

Quanta - Meso Blue | Quanta Lights

Don’t let the price confuse you, this light kicks out a seriously wide blue spectrum for your corals. A great supplemental light that adds additional violet light to fill in where other lights miss. Since they are lightweight mounting them to your already existing lighting system is super easy...

www.quantareef.com

Opp's looks like the "inexpensive" bars have only one color choice,

PicassoDan · Aug 24, 2022

The cheap diodes are less than $1 ea. The power supply still works. Mainly, this just seems like an easy thing to do, and for <$50, I have a new light. I'm also curious to compare it to the new XHO unit.

oreo54 · Aug 24, 2022

PicassoDan said:
The cheap diodes are less than $1 ea. The power supply still works. Mainly, this just seems like an easy thing to do, and for <$50, I have a new light. I'm also curious to compare it to the new XHO unit.

Yea I get it. I was a bit harsh in my above post.
Tricky thing will be finding drivers that fit.
From the looks of the one I'd replace all 4 most likely.
You could eliminate them all together and replace it with a simple resistor.
Changing from constant current to constant voltage.
What you would need is finding out the new strings real V(f).
A 5w " class" ( probably overkill) resistor at around 10 ohms should work.
Under ( sometimes way under) $1 each.

You can get more precise by using real world numbers After one new board is assembled and if you have any functional drivers you can fire it up and measure the real V (f) at 350mA.

An advantage to the conversion is you could add a cheap $4 manual dimmer.

Depending if the center slug is soldered or just attached with thermal compound will make it more or less difficult to remove the old ones.
You could try an electric frypan to desolder a whole board at a time.
Old school just desolder the contact ends a more than likely just breaks the old diode apart with a twist .
On reassembly thermal adhesive in the center and solder arms "Heatsink plaster" is a common thermally conductive electrically insulating silicone.

Last " catch" using resistors can " waste" power.
At 24v and a single diode V(f) of 3.5 v and 350mA of current your total wattage of 4 6 diode bars in series parallel is 34.3 watts with 4.9 watts as waste heat in the resistors.
Closer the power supply voltage gets to the V(f) of the string the more efficient it gets.
With a 24 v and 6 diode string obviously the ind. diode voltage should approach 4v.
That's the voltage each of 6 would receive without a resistor. They wouldn't live long.
Thus the constant current advantage.

Some bars still run cv.
Most small diode strip lights as well.

Trend is cc.
You can play with this calc
Just use voltage sum of 6 in series

https://www.digikey.com/en/resources/conversion-calculators/conversion-calculator-led-series-resistor

Or this one.

LED Series Resistor Calculator

LED series current limiting resistor calculator - useful when designing circuits with a single LED or series/parallel LED arrays - for both the common small-current (20mA) LEDs and the more expensive, high power LEDs with currents up to a few Amperes. The LED calculator will display the...

www.hobby-hour.com