COB efficiency Spreadsheets

[ledgardener]

What is stopping one from wiring in parallel using constant current drivers?

If you have a low voltage CC driver, nothing stops you. I have 2 Vero 18s running in parallel on a single 1400mA CC driver right now that is rated to do its current between 9V and 42V.

I hooked them up this way just as an experiment. What I found is that the driver will still output its rated current no problem, but the COBs do not split the current evenly. They are very stable. One consistently draws about 750mA, and the other will draw 650mA - even over the course of several hours they draw the same current, give or take a milliamp or two.

 

[Plant Lobbyist]

If you have a low voltage CC driver, nothing stops you. I have 2 Vero 18s running in parallel on a single 1400mA CC driver right now that is rated to do its current between 9V and 42V.

I hooked them up this way just as an experiment. What I found is that the driver will still output its rated current no problem, but the COBs do not split the current evenly. They are very stable. One consistently draws about 750mA, and the other will draw 650mA - even over the course of several hours they draw the same current, give or take a milliamp or two.

I agree and run them in parallel all the time. The question was to weitfras but his history of posts shows that he is one of 'those less smart' ones around here.

 

[ledgardener]

I agree and run them in parallel all the time. The question was to weitfras but his history of posts shows that he is one of 'those less smart' ones around here.

Sorry - I didn't clue in that it was intended for him in particular.

 

[wietefras]

I agree and run them in parallel all the time. The question was to weitfras but his history of posts shows that he is one of 'those less smart' ones around here.

Are you really this dense that you think your exception is the norm?

Don't have time for idiots like you though, so ignored.

 

[alesh]

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.

Great answer, thanks. In simpler words, CC in the 18-36V region, CV when >36V is required to pull 5.2A through the whole cicruit, right? And the difference to "C" would be that they don't hold CV once they're out of their CC region?

 

[alesh]

@alesh, The obvious and biggest difference is that on the "C" (CC) you wire the COBs in series and on the "non-C" version (CC+CV) you wire them parallel.

Most of the time, yes.
But you can use a suitable "C" (CC) driver to drive COBs in parallel. I use HLG-240H-C2100 to drive 4 Vero29-C, 2 parallel strings of 2. I'm also pretty sure you could use a suitable "non-C" version driver to drive a series of lower voltage COBs.

Anyway, I believe I understand the difference now.

 

[ledgardener]

Great answer, thanks. In simpler words, CC in the 18-36V region, CV when >36V is required to pull 5.2A through the whole cicruit, right? And the difference to "C" would be that they don't hold CV once they're out of their CC region?

Simple answer is that a CV+CC driver will run in CC mode when rated max current is exceeded, and CV mode at any level of current less than rated max.

The only part of your answer Im not sure about is where you say "CV when >36V is required to pull 5.2A through the whole circuit". With this driver, you should never see voltage greater than 36V on the circuit unless you manually adjust it higher (the model we were talking about can be adjusted up to 40V using the pot I believe).

The driver itself is dictating the voltage of the entire circuit while it is in CV mode, and you won't see it any higher than 36V. Once it switches to CC mode, the forward voltage of the COBs begin to dictate the voltage output of the driver, but it can only decrease at that point.

I think your explanation of the "C" series makes sense.

 

[Baura]

just FYI, i dont know if theres a thread about it or if anyone saw that but:

Revision: 28 (December 19, 2016):
http://www.cree.com/~/media/Files/Cree/LED-Components-and-Modules/XLamp/XLamp-Application-Notes/LM80_Results.pdf

CLD-AP05 rev 3G (updated from 3F to 3G)
http://www.cree.com/~/media/Files/Cree/LED-Components-and-Modules/XLamp/XLamp-Application-Notes/XLampThermalManagement.pdf



I just couldn't find any useful NEW information, but at least we nerds got something to look at....

 

[MarCus M.D]

Is there any comparative graph of efficiency in lumens, between the CXB3590 DB BIN, Vero29 Gen7, CLU058-1825 and 240pcs Samsung LM561C?

Which is more efficient at different Amp?

 

[ttystikk]

Is there any comparative graph of efficiency in lumens, between the CXB3590 DB BIN, Vero29 Gen7, CLU058-1825 and 240pcs Samsung LM561C?

Which is more efficient at different Amp?

While I don't have the exact data in front of me, all these chips are quite similar in terms of efficiency and spectrum output; the blanket thrown over all of them is pretty small.

Therefore the decision comes down to cost. At low current, the 561C chips on Quantum Boards will have a cost advantage because there will be no need for a heat sink. Even when a heat sink is figured in at higher current, they're still competitive. The Cree CXB3590 on the other hand is a good chip in the same class, but it's currently priced well above the others.

Those with more up to date information please feel free to correct me.

 

[CobKits]

4 1212s on a slate 2 heatsink (which is really too thin for cobs) is equal to a QB on same heatsink

if i had to guess, with good passive pinfins, 2 vero C or citi 1825 would top a QB at all wattages. these chips are generally 2.5X the wattage of a 1212 at a given efficiency

a cxm32 or 3618 gen6 might match a QB on a good heatsink, i have yet to test, just a guess

 

[Green_Skunk]

Nowwwww he gets it.... thank GAWD

Don't worry I think I'm the next "Doer" in line ......<kicks rocks>

Oh wow I didn't realize this thread was from 2015....

 

[voon]

Simple answer is that a CV+CC driver will run in CC mode when rated max current is exceeded, and CV mode at any level of current less than rated max.

The only part of your answer Im not sure about is where you say "CV when >36V is required to pull 5.2A through the whole circuit". With this driver, you should never see voltage greater than 36V on the circuit unless you manually adjust it higher (the model we were talking about can be adjusted up to 40V using the pot I believe).

The driver itself is dictating the voltage of the entire circuit while it is in CV mode, and you won't see it any higher than 36V. Once it switches to CC mode, the forward voltage of the COBs begin to dictate the voltage output of the driver, but it can only decrease at that point.

I think your explanation of the "C" series makes sense.

So if i understand it properly .. CV driver version examp.,, HLG-185h-36A ,, it works like CC + CV, that yes? When using adj.Voltage on the internal CV potentiometer, it determines as the CV output on the chip and in addition to this voltage level, it will withdraw the corresponding current .. if I do not exceed the 5.2Amper limit parameters for 3xCOB 1212 @ 36V = 1600mA on the COB ,,according to the data sheet,, the driver control function will be maintained CV (CV ~ 36V @ 4,8A). If it exceeds the 5.2A limit by using more COB on the controller on parallel wiring ,,4xCOB 1212 @ 36V for the example ,, .. the driver starts to lower the voltage so that it reaches the limit of 5.2A for 4 COB @ 1.3A @ 35.3V. Such a connection is much more variable in all settings .. where I can use both CV and CC .. For example .. CLU048-1212 3000k80CRi @ 33V @ 400mA .. on driver adj. Voltage 33V .. Can I connect 6 to 13 pieces CLU048-1212 to CC @ 400mA .. if i call adj. Vol 36V ..CLU048-1212 3000k80CRi @ 36V @ 1600mA .. I can connect 1-3 pieces for ConstantCurrent mode @ 1600mA =4.8A or set up adj.Voltage on driver to max. limit 40V at run 3xCOB@ on maximum load 1733mA@37V.. Is it understandable to me?

 

[Devildenis69]

Hey guys !

Is there an efficiency calculator somewhere for citizen and luminous ?
I would like to know the % of CXM-22 and 12xx at 0.5A

I find only the spreaddheet for the 1212 and 1818 on this thread

 

[bullSnot]

Hey guys !

Is there an efficiency calculator somewhere for citizen and luminous ?
I would like to know the % of CXM-22 and 12xx at 0.5A

I find only the spreaddheet for the 1212 and 1818 on this thread

I am not good enough that I only need to dial in lights. my cree COB work fine...I am the weak link that needs more time in the craft

 

[DrBlaze]

Hey guys !

Is there an efficiency calculator somewhere for citizen and luminous ?
I would like to know the % of CXM-22 and 12xx at 0.5A

I find only the spreaddheet for the 1212 and 1818 on this thread

Here is the Citizen gen6 calculator: http://ce.citizen.co.jp/lighting_led/en/products2/notice_Simulator_ver6.html

There is no calculator for the cxm-22, but in the bottom graph you can see it is a bit better than the citi 1818 in performance, with prob a 2% efficiency gain. Since both chips are the same voltage, just use the 1818 data for the cxm-22

 

[Dave455]

Here is the Citizen gen6 calculator: http://ce.citizen.co.jp/lighting_led/en/products2/notice_Simulator_ver6.html

There is no calculator for the cxm-22, but in the bottom graph you can see it is a bit better than the citi 1818 in performance, with prob a 2% efficiency gain. Since both chips are the same voltage, just use the 1818 data for the cxm-22

View attachment 4027713

Where would quantum board show on chart ?

 

[salmonetin]

...sorry bros ...where are the last efficiency spreadsheets?....

...new version of kanna spreadsheet... bulbs analyzer 1.3... thanks to Wilson...

....then my Fusion Spreadsheet go to version 1.4 .... the torture never stops...

pd... sorry not public version...yet... maybe on future... who knows...



Saludos

 

[DrBlaze]

Where would quantum board show on chart ?

https://www.rollitup.org/t/par-test-of-cobs-vs-samsung-561-boards.942636/

 

[pollen205]

hi

how do I meassure cob efficenty..?
I have mean well HLG-185H-C1400A driver and 4 50w cobs...
In the shop they say I must buy some kind device that I put in the wall plug and then I put plug from the cob fixture to that device and that device will tell me if I supply the fixture with 200w (4x50w cobs)...or if I supplying the fixture with less or more I can on the driver with screwdriver dimm it...
or they talking about V instead of W...
I dont know but in the shop they have that device and they say it is realy importent

Am I correct about this?
What is that device and do I need it?
How will I now if my fixture is it at maximum efficenty?

please help me I know so litlle about electricity