Bigger = better for drivers?

http://www.trcelectronics.com/View/Mean-Well/HLG-150H-48.shtml

Looking at this. 3.2 amp output. Could be used to run 5 2520's or 3 3070's with ease. At $65 a pop it would replace 5x $20ish each for the 2520's plus save a boatload of wiring and mounting. Any reason not to wire in parallel and use a high output driver rather than multiple lower output units?

Efficiency, in some case or another, comes to mind. However, I have no prior knowledge of running COBs with a single driver while using a parallel configuration. Someone, with experience over this matter, should be able to adequately answer your question before too long.

Yes, the problem is regulating current through the parallel cobs. The forward voltage of each cob is slightly different at a given current, meaning if you put a bunch of them in parallel, more current will go down some cobs than others.

If you get a driver that can support 3 times the voltage instead of 3 times the current, you can drive multiple cobs in series and be guaranteed that the current through each cob is equal since they're in series.

BuddyLeeCU said:

http://www.trcelectronics.com/View/Mean-Well/HLG-150H-48.shtml

Looking at this. 3.2 amp output. Could be used to run 5 2520's or 3 3070's with ease. At $65 a pop it would replace 5x $20ish each for the 2520's plus save a boatload of wiring and mounting. Any reason not to wire in parallel and use a high output driver rather than multiple lower output units?

Click to expand...

churchhaze said:

Yes, the problem is regulating current through the parallel cobs. The forward voltage of each cob is slightly different at a given current, meaning if you put a bunch of them in parallel, more current will go down some cobs than others.

If you get a driver that can support 3 times the voltage instead of 3 times the current, you can drive multiple cobs in series and be guaranteed that the current through each cob is equal since they're in series.

Click to expand...

That gets tricky...and dangerous. Trying to run 5x 2520 would require 12ga wire and be considerably more dangerous to work around since each surface soldering point would be live @150v or more.

What about putting a resistor on each line to balance current?

You don't need nothing heavier than 20ga if you run 5x2520 in series. 150V point is of course valid. I wouldn't be much concerned, though.
16ga wire required for MW HLG-150H-48.

Wire gauge would only need to be thicker if more current was going over it for longer distances. Running at a higher voltage actually prevents the need for fatter wires by allowing you to run less current.

I agree that high voltage is dangerous, but under 200V DC isn't high voltage, it's medium voltage. High voltage is 50,000 volts. You've got gaping holes with ~170V magnitude AC sticking all over your walls and extension cords. If you have a power strip, it's full of ~170V magnitude voltage holes. Do you have a desk lamp? It's probably powered directly off ~170V AC. Any of those connections could electrocute you. And a sharp knife could cut your skin and cause you to bleed, to death if you're not careful.

My point is that 150V is dangerous, but not THAT dangerous. There are pros and cons to running at a higher voltage. You will need better insulation to protect from shorts/leaks/shocks, but current limiting will be easier, and you won't have to worry as much about a fire starting from too much current burning a wire.

BuddyLeeCU said:

That gets tricky...and dangerous. Trying to run 5x 2520 would require 12ga wire and be considerably more dangerous to work around since each surface soldering point would be live @150v or more.

What about putting a resistor on each line to balance current?

Click to expand...

Efficiency is not really a factor, in fact it's generally more economical to get bigger drivers for multiple cobs if you want to get a more efficient driver.

churchhaze said:

Efficiency is not really a factor, in fact it's generally more economical to get bigger drivers for multiple cobs if you want to get a more efficient driver.

Click to expand...

So it's more efficient and economical to have multiple drivers (more so big than small?) assigned to multiple COBs or have I misunderstood your explanation?

Actually I'm reading this while standing in front of an xray machine. We should use these suckers to run our LEDs. I can get 24,000- 125,000 V at 300mA. How many Veros in series can I run on this ?

(3571) vero 29 @ 300mA

But don't go near it or it could shock you through the air!! lol You could easily have arching through the heatsink, so you might want to cover the entire light in some sort of resistive coating..

AquariusPanta said:

So it's more efficient and economical to have multiple drivers (more so big than small?) assigned to multiple COBs or have I misunderstood your explanation?

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Bigger, higher voltage drivers are generally more efficient and also cheaper per watt. But the economy depends on what can you get. There are some smaller cheap china drivers (1 per COB) which are efficient enough for a really good price. They're probably most economical solution. On the other hand, you have no guarantee how long they will last.

Yep if you went with a high current driver you would need thicker wire and a challenge balancing the strings, but with a high voltage driver you need a wire with a proper jacket voltage rating. True the solder points are hot and so are the connectors. There are things you can do to to protect yourself (fast blow fuses, GFCI, extra insultation) but the major difference is, don't work on or adjust your modules while they are switched on and ground your heatsinks.

As far as driver efficiency, If you go with the Meanwell HLG-185H series you can get up to 94%. Most other Mean Well drivers are 85-91%. The individual 1.45A drivers from eBay are 90-91% efficient.

The cheapo drivers have a wider range of fluctuation in their specs than the Mean Wells and I agree the Mean Wells should have much better reliability long term. On the other hand, we have seen a very low failure rate in the quality Chinese drivers. I came across some cheapo drivers a few years back that are 700mA dimmable, capable to drive a CXA3590 (80Vf) and often run at 93% efficiency. So it can be done from an engineering standpoint but there is a big hole in the LED driver market.

Good advice. This has sort of slipped my mind to be honest. I think I will connect the green wire from the wall to one of the hanger screws.

SupraSPL said:

ground your heatsinks.

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What I'm not sure about is whether this would even trip the breaker. What would happen if you shorted the current supply? Would it put out more than it's rated current?

I'm not about to test.

I figure if you have a fast blow fuse close to the DC output of your drivers and your heatsink is grounded, that eliminates the possibility that the heatsink could ever become live and "surprise" you lol.

It may not be necessary to add a fuse to the Mean Wells though because they have short circuit protection built in. So grounding your heatsinks is enough to gain that protection.

SupraSPL said:

... On the other hand, we have seen a very low failure rate in the quality Chinese drivers. I came across some cheapo drivers a few years back that are 700mA dimmable, capable to drive a CXA3590 (80Vf) and often run at 93% efficiency. So it can be done from an engineering standpoint but there is a big hole in the LED driver market....

Click to expand...

That's good to hear that these drivers do well. I've been wondering, do you know something about drivers from this company? Seems like a good deal for the money.

So...

Does anyone have a good idea for a 120v or so driver that could run 3x 2520 or 3070s?

And link to the Chinese drivers? I searched alibaba before and aliexpress but was a horrific mess trying to find heatsinks and drivers.