Angrysanta Posted January 31, 2014 Share Posted January 31, 2014 Hello there, Using a group buy 250w 5.2a psu how would I run 3 of the above LED clusters. I need to use LDD drivers due to PWM dimming. Thanks Simon Link to comment
jedimasterben Posted January 31, 2014 Share Posted January 31, 2014 The 250w power supply is fine to run three of the 5.2. Link to comment
Angrysanta Posted January 31, 2014 Author Share Posted January 31, 2014 So using the interconnects on the website I could use one LDD for all of one channel in all three clusters. So I would only need 5 LDD to run the whole thing. Cheers Link to comment
jedimasterben Posted January 31, 2014 Share Posted January 31, 2014 One LDD can run two channels of the 5.2, not three, that's pulling too much voltage and will damage the LDD or the LEDs (or both). I think that to run three you need two with the interconnects, and one with dual Molex connectors. Link to comment
Angrysanta Posted January 31, 2014 Author Share Posted January 31, 2014 That's a shame as one set(5) of LDD will be used to its potential but the other set(5) only less than half which is inefficient. Link to comment
jedimasterben Posted January 31, 2014 Share Posted January 31, 2014 The LDD are efficient no matter what output voltage they have. http://www.meanwell.com/search/LDD-H/LDD-H-spec.pdf Page 3, final graph. At 50% load they are still ~92% efficient minimum. Link to comment
Angrysanta Posted January 31, 2014 Author Share Posted January 31, 2014 Impressive stuff. So do you think three is enough for a 4" 240l tank? Link to comment
jedimasterben Posted January 31, 2014 Share Posted January 31, 2014 What are the dimensions? Link to comment
Angrysanta Posted January 31, 2014 Author Share Posted January 31, 2014 120X48X40 (l x h x w) cheers Link to comment
jedimasterben Posted January 31, 2014 Share Posted January 31, 2014 I take it those are cm Basically 48" x 19" x 16". three of them would work well on that size tank. Link to comment
Angrysanta Posted January 31, 2014 Author Share Posted January 31, 2014 Sorry for that. I'll go and do some working out then. A 36" GB heatsink would be fine?? Link to comment
Timmydatoolman Posted January 31, 2014 Share Posted January 31, 2014 FYI on the inter connects, the will only allow you to place the lumia 17" inches apart. Probably not a big deal but I wanted mine 18" apart so now I have to splice the wires. Link to comment
jedimasterben Posted February 1, 2014 Share Posted February 1, 2014 ^best user name ever. Link to comment
Angrysanta Posted February 1, 2014 Author Share Posted February 1, 2014 Is a 36" heat sink correct or could I use a 24"?. Link to comment
jedimasterben Posted February 1, 2014 Share Posted February 1, 2014 As far as cooling goes, the 24" would be OK, but you wouldn't be able to space them out as much. Link to comment
Angrysanta Posted February 1, 2014 Author Share Posted February 1, 2014 So 36" would give best coverage? Link to comment
jedimasterben Posted February 1, 2014 Share Posted February 1, 2014 It would allow you to space it out some more. Link to comment
Angrysanta Posted February 1, 2014 Author Share Posted February 1, 2014 Thanks for your advice. Simon Link to comment
Paleoreef103 Posted February 3, 2014 Share Posted February 3, 2014 Do 4. Not 3. The 5.2s seem designed to run in pairs. And coverage would be superior, you can always turn them down. You'll have everything else you need, bought already. Almost... It will change which heatsink or heatsinks you go with, of course. Either two short ones, so youll have your own Radion style. Or one long 48" heatsink with the 5.2s spaced evenly. Youll need to upgrade your power supply to handle the 280 watts, but I don't think that's a big jump in price from the 250w. So, for just a litlle more than $120 difference, you can have 1/3 more light. And it will be symmetrical, with superior coverage. Edit: I think when I calculated wattage, it was close to 75w, but they are listed as 70w. Me, I would design around 75 watts per Lumia. I'm with you on this especially for LDD drivers. One question. Wouldn't you actually need a 250 for running a pair of Lumia 5.2s? The power supply actually puts out 48V and 3.75 Amps not 180W divided however you choose. If you run the Lumia at max suggested currents using LDDs (well... the pure cree strings at 1A instead of 1.5A), you'll be using 2 - 1A LDDs and 3 - 700mA LDDs. That's a total of 4.1 Amps from the driver. OR is it more important that the LDDs are drawing no more than 36W @ 700mA or 33W @ 1A? I'm not that versed in power supplies in this instance. Link to comment
jedimasterben Posted February 18, 2014 Share Posted February 18, 2014 I'm with you on this especially for LDD drivers. One question. Wouldn't you actually need a 250 for running a pair of Lumia 5.2s? The power supply actually puts out 48V and 3.75 Amps not 180W divided however you choose. If you run the Lumia at max suggested currents using LDDs (well... the pure cree strings at 1A instead of 1.5A), you'll be using 2 - 1A LDDs and 3 - 700mA LDDs. That's a total of 4.1 Amps from the driver. OR is it more important that the LDDs are drawing no more than 36W @ 700mA or 33W @ 1A? I'm not that versed in power supplies in this instance. You size the power supply by wattage, not by amperage. Add up everything and then give around 20% extra, so two 5.2 would be ~150w total, with 20% extra the power supply should be 180w or greater. Link to comment
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