the HLG-600H thread

BOBBY_G said:
no, because the cobs are wired in parallel. 16.7A would be split according to number of cobs

[email protected]
10@ 1.67A
20@ 0.835A
etc

the 16.7A is fed thru two pairs or 14GA conductors coming out of the driver. im gonna land each pair of them on one of these

http://www.ebay.com/itm/MARINE-DUAL...AR-5-GANG-BLUE-SEA-SYSTEMS-2722-/231806506109

and take off cobs from there. 18GA only sees current for individual cobs

easy breezy
Click to expand...

Ah I see, it seemed like you were going to run 18awg throughout the circuit. The connection between the driver and cobs ( or your bus bar in this instance) was my point of concern. carry on then. :p

I need more sleep for proper communication
 
BOBBY_G said:
i wanna run my cobs hard on the first run, and use that to buy more

was thinking the 600H because of its high efficiency and versatility

something like: 8 3590 s @ 2.08V to start, at 50% efficient
then buy 8 more and run them @ 1.04A and bump the efficiency up to 60%
then top out at 24-32@ 600-750mA @ 64-67% efficiency

other than the wiring involved, why would i not want to do this? would make the sure i got the most out of each driver in the future
Click to expand...

I would be worried about thermal runaway when running in parallel. Not that you couldn't design a protection circuit for running these in parallel, but that would put a hit on efficiency. If you look at the design PDF from cree they say if running multiple CX* series cobs that they should be run in series. Been away for awhile but notice a guy that has been doing parallel for three years had a mishap where his set up caught on fire. But that is why cree and bridgelux and I am sure other cob makers tell you not to run these in parallel.

Edit: here is the bridgelux one
 
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JavaCo said:
I would be worried about thermal runaway when running in parallel. Not that you couldn't design a protection circuit for running these in parallel, but that would put a hit on efficiency. If you look at the design PDF from cree they say if running multiple CX* series cobs that they should be run in series. Been away for awhile but notice a guy that has been doing parallel for three years had a mishap where his set up caught on fire. But that is why cree and bridgelux and I am sure other cob makers tell you not to run these in parallel.

Edit: here is the bridgelux one
Click to expand...

I think he had a trick up his sleeve for stopping thermal runaway issues in their tracks.
 
I have talked with Bridgelux's engineers about this and was told it had more to do with inconsistent output of light between COBs. As long as we have enough COBs on a driver for more than one to fail without over powering the rest, we should be fine. Every light I have bought from China with Meanwell drivers has been run in parallel. I have run multiple setups in parallel with no problems. The engineer said that there shouldn't be any fire safety issues with this setup the way we run our panels. What I mean is, if your can safely run your panel with one of your COBs disconnected, the whole panel won't fail. Now if you are running, let's say, a HLG 600 with only 6 COBs and one fails, now you are pushing the limits of the COB, I can see thermal runaway happen. But if you run 10 on the same driver, you could loss 4 COBs before you system is in trouble. For those that are still paranoid, you could check forward voltage and remove any COB that is running at a voltage with to much difference. I have done this with both Vero 29s and China's Bridgelux version COB. The voltage difference was within .03volts, so I no longer bother checking.
Please feel free to call Cree, explain how we run are panels (soft with overkill on cooling) and see if they have any concerns as far as safety. I personally don't care if one COB is putting out a couple of lumens less or more. I still like using CC/CV drivers for the simplicity. Pick a wattage you want and add COBs until it's safe.
 
JavaCo said:
I would be worried about thermal runaway when running in parallel. Not that you couldn't design a protection circuit for running these in parallel, but that would put a hit on efficiency. If you look at the design PDF from cree they say if running multiple CX* series cobs that they should be run in series. Been away for awhile but notice a guy that has been doing parallel for three years had a mishap where his set up caught on fire.
Click to expand...
link? what can we learn from this? does the current limiting protection eat up more juice than the efficiency penalty of the constant current drivers?

an obvious design consideration when running parallel is to match the chips for Vf. chips from one lot should all test pretty close i would imagine.

keep in mind that the chip mfrs are expecting you to run these at higher currents. if you had 16 chips on an HLG-600 pulling 1050 ma each would it matter if there was up to 10% variation in Vf and some ran at 950 and some at 1150? obviously this is an issue at 3000 mA and above....

also do the math on dropping one chip out of 16. your current would jump from 1050 to 1113

what if you were running 5 chips at 3350 mA - drop one of those and youre over 4A and could* blow the whole lot

*depending on the driver voltage control and overvoltage protection. if the driver doesnt let the voltage rise over 38.5V, the chips cant pull over 3600 mA....
 
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BOBBY_G said:
would it matter if there was up to 10% variation in Vf and some ran at 950 and some at 1150? obviously this is an issue at 3000 mA and above....
Click to expand...

a variation of +/- 5% or 10% on Vf will change the current between 1100mA to 3200mA...

a variation of just 1% will change the current at about 200mA

have a nice day... in your parallel world

vf cfd.JPG
 
yes but youre assuming forward voltage (a measure of the voltage drop of a diode at a give current) is the same as applied voltage

if you have 3 chips
one is 35.5V at 2000 mA
one is 36V at 2000 mA
one is 36.5V at 2000 mA

what happens when you put 36V across them? the 36.5V one will draw less current and the 35.5V will draw more, but again within limits

do we actually know the Vf tolerance on chips? datasheet is unclear. perhaps one of the fixture mfrs can chime in @Rahz @Greengenes707 @Stephenj37826

youd think that anything sufficiently out of spec would bin differently
 
BOBBY_G said:
what happens when you put 36V across them? the 36.5V one will draw less current and the 35.5V will draw more, but again within limits
Click to expand...

your LIMITS
shifting the curve to 2Amps for the different Vfs," roughly"
current for the fix Voltage and different leds are now 1770mA; 2000mA; and 2300mA , for a fix temperatur.



cree 36.JPG
 
seems reasonable. when i do my 600 build ill measure across each chip and pull the highest and the lowest out and see how close the rest are, ill bet i can get +/- 5%ish on current/luminosity
 
BOBBY_G said:
link? what can we learn from this? does the current limiting protection eat up more juice than the efficiency penalty of the constant current drivers?

an obvious design consideration when running parallel is to match the chips for Vf. chips from one lot should all test pretty close i would imagine.

keep in mind that the chip mfrs are expecting you to run these at higher currents. if you had 16 chips on an HLG-600 pulling 1050 ma each would it matter if there was up to 10% variation in Vf and some ran at 950 and some at 1150? obviously this is an issue at 3000 mA and above....

also do the math on dropping one chip out of 16. your current would jump from 1050 to 1113

what if you were running 5 chips at 3350 mA - drop one of those and youre over 4A and could* blow the whole lot

*depending on the driver voltage control and overvoltage protection. if the driver doesnt let the voltage rise over 38.5V, the chips cant pull over 3600 mA....
Click to expand...

Not sure what you want a link to. You can find the design PDF's on crees and bridgelux web sites. The guy that had his cobs go up in smoke was in here about 6 or 7 days ago , so it could be 10 to 20 pages back. Pretty sure he said it was two Vero 18's he was running in parallel. Dont have any sources for a circuit for protection, but low wattage leds run in parallel they usually slap a resistor on them to keep them from current hogging. You can google it and see what you can come up with. Dont think resistors would be a good option for high current cobs , Diodes would be the best option I believe. If it was me i would just run two of the new hlg 320's and run the cobs in series then no need to worry about it.
 
You are assuming that the people you are recommending the HLG320c know what they are doing when it comes to electricity? I personally don't recommend a newbie to use the higher out put drivers unless they are in parallel and running soft. The voltage is extremely high when running soft on a Constant current only driver. Even some of the super high output COBs I have run over 100 volts by themselves. If someone doesn't understand the importance of wire diameter, wire ratings, know when they have a good solder connection, etc. the simplicity of less, larger drivers become dangerous. Just my 2 cents.
 
yeah i would never take anyone elses advice on electrical safety. nor would i be responsible for anyone elses. maybe i need to add a disclaimer to my signature
 
nevergoodenuf said:
You are assuming that the people you are recommending the HLG320c know what they are doing when it comes to electricity? I personally don't recommend a newbie to use the higher out put drivers unless they are in parallel and running soft. The voltage is extremely high when running soft on a Constant current only driver. Even some of the super high output COBs I have run over 100 volts by themselves. If someone doesn't understand the importance of wire diameter, wire ratings, know when they have a good solder connection, etc. the simplicity of less, larger drivers become dangerous. Just my 2 cents.
Click to expand...

All AC to DC drivers are dangerous. It is true that the low voltage DC output drivers can only kill you on one end , they all should be treated with respect. The AC input side is more than enough to kill a person. If your receptacle plug ins are wired with 14 AWG they should be hooked to a 15 amp breaker and if you have 12 AWG wire they will be on a 20 amp breaker. So thinking you are safe using a low voltage AC to DC driver is not smart in my opinion. If someone doesn't have the skillz to wiring stuff up safely they should learn from someone that knows what they are doing or not mess around with it. If someone has the respect and skillz to wire up the AC side safely ,then they should have no troubles wiring up the high voltage DC side using the same respect for safety.

Personally I believe the fire hazard part has more potential for lost life then if you screw up and electrocute yourself. For example you are running cobs hard in parallel lose one and the rest go up in flames. Grow room or tent catches on fire house burns down with everyone in it, maybe even a neighbor's house or two goes up also. Quite a few could die along with pets. Whereas if you don't know what you're doing and electrocute yourself at least you're the only one that dies.

There is a reason Bridgelux and Cree do not recommend running cobs in Parallel so it is not just me saying it. Sure if you run them soft it does give some measure of redundancy to the circuit. But running them hard is a fire waiting to happen in my opinion. Even running them in the middle could be a problem if say towards the end of their life you lose a few COBs within hours of each other while say you are at work or out partying. At least i know in series if a cob goes out the string quits working there won't be a domino effect that fries all my COBs and possibly start a fire.
 
I have seen to many builds with dangling wire, tape holding things together, etc. and I never recommended running them hard in parallel, just the opposite. I have watched a COB fry, and there were no flames, maybe a little smoke, but that was it. I would worry more about an 18g unrated wire running 400+volts melting across the fixture. No matter what way you build you are in control of your own safety.
 
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