nevergoodenuf
Well-Known Member
I think you have that backwards. It runs in CC mode pulling full amps until it hits the set voltage. Then, if it hits the voltage ceiling, it will reduce amps to maintain that voltage.
COB efficiency Spreadsheets
- Thread starter nogod_
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nevergoodenuf
Well-Known Member
@ledgardener The 18v min would be the lowest voltage the driver will run at.
ledgardener
Well-Known Member
Check this out from the Mean Well site
nevergoodenuf
Well-Known Member
I understand that and have read it before, but the second you turn your light on it is pulling full amps unless your setup is trying to pull more voltage than the limit. So, for the way we build, it is really just running as a CC
ledgardener
Well-Known Member
You're strictly talking about running a system where you have more current draw than the rated output of the driver, correct? The way I understand it is if your COBs were pulling less than the max rated current, it would run in CV mode. Once you exceed the rated current, it would then stabilize the current at max and vary the voltage to maintain the current, no?
nevergoodenuf
Well-Known Member
Yeah, but that COB will take every amp you give it until it either burns up or you run out of amps.
ledgardener
Well-Known Member
Well, if you're regulating the voltage, it will only pull however much current its particular I-V curve dictates at said voltage.
Dont the CC CV versions have two internal pots for each setting?
So if you were to set the CV at 50 and CC to 1000ma, the driver will try to give it 1000ma in CC mode unless the COB draws 50v before it draws 1000ma at which point it switches to CV mode to limit the voltage and effectively limits current as well.
Is this not how it works? After rereading the meanwell sites description Im not so sure lol
So if you were to set the CV at 50 and CC to 1000ma, the driver will try to give it 1000ma in CC mode unless the COB draws 50v before it draws 1000ma at which point it switches to CV mode to limit the voltage and effectively limits current as well.
Is this not how it works? After rereading the meanwell sites description Im not so sure lol
ledgardener
Well-Known Member
In this example, I think it would maintain a constant voltage of 50V and deliver however much current your load required, up until your load was drawing 1,000mA, where it would then switch to CC mode and hold that current steady.
This sounds right.
I'm looking for a cheap driver to run the 1212 @1400, but in the end after heatsink and drivers, it might be cheaper going with 1818 or 1812 on a cheap 55vdc @900ma....
The ldd1500h fits perfect for the 1212 right?
Cheers
bassman999
Well-Known Member
Cobs are current greedy, this is true, they will take it till the die.
wietefras
Well-Known Member
The HLG-185H-C1400B puts out 1400mA and the HLG-185H-36B puts out 36V.
Is the confusion that is CC+CV? and not just CV? Semantics?
Either way, there is a clear distinction in how you connect the COBs to these drivers and in what you can dim on these drivers and this difference is noted by the "C" in the type.
alesh
Well-Known Member
I guess I'm dumb. Be patient with me please
My confusion is how could HLG-185H-36B work as CV.
The only difference I can see between these 2 is - obviously - different I and V rating.
I really don't see how could HLG-185H-36B be anything but a CC source. It adjusts its output voltage (within its CC range) to pull rated current through the circuit, doesn't it? How could this possibly be a constant voltage source and NOT a CC one?
ledgardener
Well-Known Member
It only functions as CC once you pull max current from it. Up until that point, it is working as CV and will dish out current as required, while holding voltage steady.I guess I'm dumb. Be patient with me please
My confusion is how could HLG-185H-36B work as CV.
The only difference I can see between these 2 is - obviously - different I and V rating.
I really don't see how could HLG-185H-36B be anything but a CC source. It adjusts its output voltage (within its CC range) to pull rated current through the circuit, doesn't it? How could this possibly be a constant voltage source and NOT a CC one?
alesh
Well-Known Member
That would be a situation when a circuit connected needs more than rated voltage to pull rated through, right? And what would be the difference to "C" series? Do they try to up the voltage until they hit over voltage protection?
Plant Lobbyist
Well-Known Member
What is stopping one from wiring in parallel using constant current drivers?
wietefras
Well-Known Member
Minimal voltage on a HLG-185H-C is 127V. So you'd blow out all your COBs.
ledgardener
Well-Known Member
I might be misunderstanding what you're asking, but I'll share how I think it works. I'm hesitant to even try to answer since I've been pouring over your "Math Behind" thread the past couple days to try and understand all the info that YOU have provided!
Anyway, here goes: If you're using a constant voltage driver that has a max current output of 5.2A and is set to output a constant 36V, as you connect each COB in parallel, the voltage across each of them will remain constant at 36V and the driver will supply each COB with however much current that it requires, which is determined by that particular chip's unique I-V curve.
At 36V, one COB might pull 2 amps, and another in parallel beside it might pull 2.1 amps. In this case, the driver is operating in CV mode and supplying 4.1 Amps to the 2 COBs with 36V across each. If you add another of the same COBs and it pulls another ~2 Amps, you have now exceeded the rated current output of the driver, and it will hold its max current steady and split it among the 3 COBs.
As the COBs are now getting less current because they're splitting the max amount the driver can output, their forward voltage will drop and the driver will lower its voltage level to compensate, while holding current at max. You can see this in the driver data sheet on the page near the bottom where it shows a graph of the voltage and current output relationship.
A constant current driver will operate in this manner right from startup, and will automatically vary the output voltage required to push its rated current through the circuit.
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