CoralVue Dimmable eBallasts

[wlagarde]

I just purchased 2 of the 400W version of these ballasts. They are totally silent, run very cool, and by my light meter, dim output down to about 40% of maximum.

Anyone else have any experience with these?...I was curious about what people think so far...

I plan to use these to assist in making light output constant over the life of a bulb (by burning a new bulb less than maximun as I don't need all the light 400 Watters supply and then increasing the output to maintain intensity as the bulb ages), prevent burning when new bulbs are installed, and finally to possibly lengthen bulb life.

 

[wlagarde]

Bump ^^

 

[wlagarde]

So I must be the only one using these?

 

[bureau13]

I'm not sure running halides at less than full power necessarily extends their life. I've heard just the opposite in fact, although I really don't know one way or the other. Unless you know for sure, I wouldn't assume so.

jds

 

[brad23]

If you want to run it at %40 most of the time then why didn't you just buy 250w

 

[wlagarde]

Good point. CoralVue claims it does, but I'm skeptical. It'll be interested to see how it pans out as I track output with a light meter over time.

I sure wish I had a spectrometer though so I could look at spectrum and see if it changes as one dims the ballast below maximum output. I wonder if Sanjay Joshi would be interested in looking at this?

BL

 

[wlagarde]

I'm actually running it at about 75% output with a new set of bulbs. I then took a standardized light meter reading. I'll then repeat the light meter reading monthly and increase the ballast output to keep the light intensity constant. This way I avoid brown out and prevent shocking the corals when a new bulb is installed.

BL

 

[wlagarde]

Also, I find 250W 20K XMs insufficient to maintain my corals color without actinic supplementation. 400 Watters eliminates the need for actinics...lowers cost. But, I also find 400W to be too much light (when the bulbs are relatively new) since I bought lumenarc reflectors.

 

[pjf]

Link to Information?

Link to Information?

wlagarde,

I am looking for information on dimmable MH ballasts. I cannot find any mention of these dimmable ballasts on CoralVue's website.

Will you please provide us a link to more information and to a vendor?

Thanks very much!

pjf

 

[wlagarde]

pjf -

Absolutely. They are new enough that CoralVue has not listed them yet - surprisingly. I purchased mine at - www.reefexotics.com Their service is excellent and price was the cheapest I could find online. www.customaquatic.com has them as well but the price is a little higher.

I was even thinkling of remoting the dimming control and bringing up the intensity and then back down again to simulate a more natural photoperiod.

The other thing I was considering was designing a feed back system that keeps light intsnsity set at a chosen but adjustable set point.

 

[africangrey]

Does this dim any brand of the bulbs or just the coralvue bulbs?

 

[wlagarde]

Yes - It will fire and dim any bulb.

 

[pjf]

PWM

PWM

Thanks for the links. I was able to find a little bit of information from CoralVue.

(1) The ballasts do use pulse width modulation (PWM) for dimming. This means electrical power is supplied via pulses and the width of the pulses determines the brightness. This saves electricity. PWM is superior to using a rheostat because a rheostat or resistor will produce wasted heat. I believe that the Sfiligoi ACLS dimming system also uses PWM.

(2) CoralVue has no solution to automatically vary the light intensity. Perhaps you can attach a stepping motor to the manual knob. Do let us know how you solve that.

Thanks for sharing information about this dimmable ballast with us!

 

[wlagarde]

pjm -

I confirmed their use of pwm as I was able to observe this with my oscilloscope.

One option for automatically varying light intensity would be to use a servo system (purchase from a hobby supply) to turn/control the position of the pot. The DC voltage supplied to the servo system would then determine the pot's position and thus light output.

Alternatively, if I could get a schematic of the unit it would be helpful to determine if the pot is simply dividing a reference dimming voltage to ground. If so, then the pot could potentially be removed and the reference dimming voltage supplied to the dimming circuit directly - the negative of this would of course be that it would almost certainly void the warranty...

Did you contact CoralVue directly? Do you think they might provide us with a schematic?

 

[pjf]

<a href=showthread.php?s=&postid=8990817#post8990817 target=_blank>Originally posted</a> by wlagarde
Did you contact CoralVue directly? Do you think they might provide us with a schematic?

Yes, I was able to get a response via email but did not request a schematic. Do email CoralVue your fax number and request one.

On the phone, I was only able to reach a sales representative. My initial impression was that CoralVue contracted out the PWM circuitry and is not familiar with it. Perhaps you can reach someone more knowledgeable.

 

[wlagarde]

OK -

I'll go for it. I would bet the solution is relatively simple...

BL

 

[wlagarde]

pjf -

As expected, I don't think CoralVue is going to be forthcoming with a schematic. No matter, if they don't, I'll open it up and reverse engineer the circuit and figure this one out.

Interestingly, I did find out they plan to release a similar dimming ballast later this year that has an integrated microprocessor that will simulate a natural lunar cycle.