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I need to feed a LED with 120-126v 1500w, made of two strips, 750w each (the heat being generated over a surface of 8cm x 8cm).

EDIT: This is for imaging purposes, so high CRI, is important.

COB

Datasheet about the COB:

Power: 1000-2000 Watt.
VF: DC 120-126V
IF: 8750mA(1000W) , 1300mA(1500W), 17500mA(2000W)
Chip Brand: Bridgelux
CRI : Ra80 / Ra90 / Ra95 / Ra97
Beam Angle: 120 degree
Brightness: 90-140 lumens per watt (depend on color temperature and CRI value requirements)
LED Size: 100x100 mm
Luminous Area: 80x80mm
Substrate: high quality copper

Do you recommend to transform the current directly from 230v or to use a booster from 12v (from 1 or 2 PC power supply)?

In either case, which components do you recommend (eg., https://fr.aliexpress.com/item/32863157274.html and some other tension adapter)?

I'll need to regulate the tension between 120v and 126v with one (or two) tension variators. I would like to minimize the soldering work, if any.

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    \$\begingroup\$ 1500w at 12v is 125 amps, so that isn't going to be feasible. You'll have to use a high voltage source. Component recommendations are not allowed here, so you should edit those out of your post or it will be closed. \$\endgroup\$
    – user1850479
    Commented Sep 1, 2021 at 17:38
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    \$\begingroup\$ From 12V, no way. Is this one 1500W LED or several smaller LEDs? It would most likely be easier and cheaper to use several lower power drivers, perhaps 500W ones. So please give all the information about the LED itself. \$\endgroup\$
    – bobflux
    Commented Sep 1, 2021 at 17:54
  • \$\begingroup\$ "I need to feed a LED with 120-126v 1500w." LEDs operate at, typically, 2 to 5 V. It sounds like you have an LED lamp which consists of many individual LEDs. \$\endgroup\$
    – Transistor
    Commented Sep 1, 2021 at 18:35
  • \$\begingroup\$ Can you get the same lamp but with a voltage rating of 230 V? \$\endgroup\$
    – Andrew Morton
    Commented Sep 1, 2021 at 18:47
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    \$\begingroup\$ Is this constant or variable? It must be a large space bigger than a theatre so current and wire gauge are cost tradeoffs. My 10W LEDs are blinding. You will need to define the power path lengths \$\endgroup\$
    – D.A.S.
    Commented Sep 1, 2021 at 19:59

3 Answers 3

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You drive a 1500w constant current LED with a 1500w constant current LED driver. The specs you posted explain what that driver needs to do:

VF: DC 120-126V

IF: 8750mA(1000W) , 1300mA(1500W), 17500mA(2000W)

Select a current driver that can output 13 amps with a compliance range exceeding 120-126V. For example, a ~13 amp, 100-150V driver. There is no other safe and practical way to drive such an LED. You cannot safely drive it by supplying voltage directly, a driver must regulate the current. This will be expensive given the power requirements.

As for your other comments:

made of two strips, 750w each

Your specs don't mention this and imply that it is a single strip with all strings in parallel. Are you sure?

Do you recommend to transform the current directly from 230v or to use a booster from 12v (from 1 or 2 PC power supply)?

You're going to have to use whatever your driver requires, but it will almost certainly be at least 120VAC, possibly higher.

Finally, the efficiency of that panel is modest. The best LEDs are over 180 lm/watt at a CRI of 90. Consider carefully if you want to power (and cool) a 1500w panel, or a higher efficiency panel that will produce the same amount of light with less costly power supply and cooling.

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  • \$\begingroup\$ This answer is very valuable and I did not see many important aspects. I'm asking few other details to my manufaturer. I have the feeling that this other COB (store.yujiintl.com/collections/led-cobs/products/…) is a lot easier to drive and less costly to drive (I can use directly the cheap aliexpress current boosters), but if I'm not mistaken it is even less efficient (80 lm/watt (120000lm for 1500w)) \$\endgroup\$
    – Soleil
    Commented Sep 1, 2021 at 22:54
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    \$\begingroup\$ @Soleil Higher CRI means lower lumens for the same amount of optical power, so those 95 or 98 CRI lights will require much more optical power to produce the same lumens since they "waste" power at wavelengths that people aren't very sensitive to. Use the lowest CRI that meets your requirements to maximize efficiency. \$\endgroup\$
    – user1850479
    Commented Sep 1, 2021 at 23:16
  • \$\begingroup\$ I'm actually looking for maximized CRI. Do you have sources, papers on this aspect "CRI vs efficiency" ? \$\endgroup\$
    – Soleil
    Commented Sep 2, 2021 at 9:32
  • \$\begingroup\$ I'm certain about the two strips of 750w, it's been confirmed. \$\endgroup\$
    – Soleil
    Commented Sep 2, 2021 at 9:46
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    \$\begingroup\$ @Soleil This paper discusses the effect of CRI on maximum luminous efficiency: arxiv.org/abs/1309.7039 \$\endgroup\$
    – user1850479
    Commented Sep 2, 2021 at 12:58
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The LED's will have a significant negative temp.coefficient (NTC) with this array, but the electrical power requirements are simple.

I suggest adding thermal protection (OTP) to the continuously variable constant current source.. This means you cannot use variable constant voltage or tension as the NTC would cause thermal runaway and instant damage. The low voltage version is divided into 6 arrays for more flexible welding cables, so it is advisable to use them in two series arrays to require 120V just like the HV version but may be done either way with HV insulation or use in parallel for LV safety.

More critical requirements

  • 2kW Water-cooled Heatsink , custom design

  • 2kW water cooler radiator and fan

  • Buy 2kW to 4kW Current Source (CS) LED power supply with adjustable by Pot, or voltage 0 ~10V.

  • Do not choose a power supply that is 100% utilized as this rating degrades life expectancy unless you plan on derating LED power to 1500W.

  • Voltage greatly affects cable diameter ( like car jumper or welding cable)

  • 2kW cable design :

    • 20A cable @ 60'C must be copper > 2mm D (AWG 10) for 120Vdc LED
    • 60A cable @ 60'C " " " > 4.6 mm D (AWG 5) for 40Vdc LED
    • choice of soldered fasteners or wire to LED ,

Lumens/ Watt increase 10~15% with colour temp towards blue-white as less phosphor loss occurs but hard on eyes so <= 4500 'K preferred for eyes. ? for plants?

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  • \$\begingroup\$ How do you know that there is NTC and that it is stronger with this array ? \$\endgroup\$
    – Soleil
    Commented Sep 2, 2021 at 9:35
  • \$\begingroup\$ Many thanks for the critical requirement section. This is very helpful. The cable design is impressive and I did not think about that. \$\endgroup\$
    – Soleil
    Commented Sep 2, 2021 at 9:42
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    \$\begingroup\$ All diodes have NTC effects incl. LEDs \$\endgroup\$
    – D.A.S.
    Commented Sep 2, 2021 at 14:08
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    \$\begingroup\$ @Soleil The NTC of the LEDs themselves is why you must not drive an array like this with a constant voltage source. You need an LED driver, which will compensate for the NTC by reducing voltage as the array heats up. Doing some more reading on LEDs might be good before spending a lot of money on an absurdly high power light. \$\endgroup\$
    – user1850479
    Commented Sep 2, 2021 at 15:17
  • \$\begingroup\$ @user1850479 Thanks for pointing out this aspect. Do you recommend to compensate for NTC despite a good watercooling (+10-20C over ambient temperature, which is about 20-25C) ? \$\endgroup\$
    – Soleil
    Commented Sep 2, 2021 at 15:40
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You ask " Do you recommend to transform the current directly from 230v or to use a booster from 12v (from 1 or 2 PC power supply) ?" since you are stating nominal AC mains voltages I would recommend simply using a transformer. The size you are talking about are readily available from electrical supply houses. Some are used in the machine tool industry for the controls circuit power. At that point you will have about 120VAC depending on your transformer choice. You can also get lower secondary voltages if you so choose. An advantage of the transformer is the secondary is normally isolated from ground so you can elect to ground it or leave it float.

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  • \$\begingroup\$ Which kind of transformer, and what to do with the AC voltage output of the transformer then to make it power 1500 watts of LEDs? Also, most likely you can get a complete 1500 watt LED driver that weighs and costs less than just the transformer alone. \$\endgroup\$
    – Justme
    Commented Sep 1, 2021 at 19:58
  • \$\begingroup\$ Go for the driver. You forgot to say 120-126VDC so AC was assumed. You also mentioned 220V is that 20VDC, I assumed AC? \$\endgroup\$
    – Gil
    Commented Sep 1, 2021 at 20:40
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    \$\begingroup\$ These are constant current LEDs, so using a transformer will not work. You must generate a controlled current or you will have a fire. \$\endgroup\$
    – user1850479
    Commented Sep 1, 2021 at 22:24

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