Will this work?

120h max 2.95A.185h max 4.25A

both go up to 53.5V

CobKits said:

120h max 2.95A.185h max 4.25A

both go up to 53.5V

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Thanks for the help. If spending 100+ dollars still sounds good in the morning I'll pull the trigger + it looks like I need to educate myself a little more so I don't fry my investment lol

1818 with a 120h is a safe bet as the chip can handle anything the driver can throw at it. its a more efficient chip too, if you were buying dozens of chips i might recommend the 1212 but for the single chip design like that the extra $12 for the 1818 is a no brainer

CobKits said:

1818 with a 120h is a safe bet as the chip can handle anything the driver can throw at it. its a more efficient chip too, if you were buying dozens of chips i might recommend the 1212 but for the single chip design like that the extra $12 for the 1818 is a no brainer

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If adding one more engine would double my coverage. I'm using a closet with 2×4' of usable floorspace. In the next couple of months I'm going to need expand my coverage in order to veg my clones.

Walterwhiter said:

If adding one more engine would double my coverage.

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it wont, really. you'll still have 150W with two engines on that driver, albeit ~20% more efficient because you'll be running them softer. considering the better coverage youd be getting with two fixtures and maybe add 30-40% to your space but doubling would be a stretch

CobKits said:

it wont, really. you'll still have 150W with two engines on that driver, albeit ~20% more efficient because you'll be running them softer. considering the better coverage youd be getting with two fixtures and maybe add 30-40% to your space but doubling would be a stretch

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OK I've been studying a little. So if the driver puts out 53.5v and the fan uses 12v. 53.5-12= 41.5v for a 50v cob would mean the cob is running at 80ish% power? I'm trying to better understand this so I can set myself up for the long game.

Also on the 18th model I would have to use the 1825s because the amps are so high? And on the 120H model the output amps would be too high to run the 1212?

Ugh tramadol is kicking in Bed Time!

You run your fan on something like an APV 12-12 or somethibg . Not the LED Driver

Walterwhiter said:

OK I've been studying a little. So if the driver puts out 53.5v and the fan uses 12v. 53.5-12= 41.5v for a 50v cob would mean the cob is running at 80ish% power? I'm trying to better understand this so I can set myself up for the long game.

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no fans use like 250 mA so you wouldnt want it on same driver. nor is this a constant current driver. nor will a 50V cob light up (at all) at 41V.

1818 will run on both a hlg-120h-48A and a -185h-48a BUT at some point it will top out on voltage and thats all you'll get. i want to say its around 2.7-3.3A but id have to test it

What I'm not understanding is if or how amperage effects the forward voltage of the cob.

How does a 48v driver drive multiple 36v cobs?

I'm basing my info on the Growmua5 YouTube video.

in parallel

Airwalker16 said:

Yep. That will work... I think the hlg 48 has 2.5 amps. @CobKits can that clu048 handle that?

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I use 5the same PS for my supplemental leds. They have a 200-48 is 2 amps, and they have a 300-48. I would go with the 3 amp model the 48-300. peace

CobKits said:

in parallel

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Still over my head. Any info leads something I can read or watch? Lol do I just need to start with basic electrical and work my way up?

HLG-120H series is a 120W AC/DC LED driver featuring the dual mode constant voltage and constant
current output. HLG-120H operates from 90 305VAC and offers models with different rated voltage ranging
～
between 12V and 54V. Thanks to the high efficiency up to 93.5%, with the fanless design, the entire series is
able to operate for -40
~ +80
°C°C
case temperature under free air convection. The design of metal housing
and IP67/IP65 ingress protection level allows this series to fit both indoor and outdoor applications.
HLG-120H
is equipped with various function options, such as
dimming methodologies, so as to provide the optimal design
flexibility for LED lighting system

Function options
Rated output voltage (12V/15V/20V/24V/30V/36V/42V/48V/54V)
Rated wattage
Series name

http://www.meanwell.com/mw_search/HLG-120H/HLG-120H-spec.pdf

im not sure if that answers your questions but you def should get a handle on basic electricity before attempting a diy job

http://www.allaboutcircuits.com/tex...chpt-5/what-are-series-and-parallel-circuits/

in this case "battery" = "driver" and "resistor" = "LED"

in the "series" configuration like in growmaus vids, the driver you use spits out a "constant current" , like 1400 mA or whatever. lets look at a datasheet

http://www.mouser.com/ds/2/260/HLG-185H-C-SPEC-806161.pdf

you will see for the -1400 model, the constant current region is 72-143V. so as long as your cob voltage adds up to 72-143V they will light up at 1400 mA

so you can use 3 or 4 36V cobs, 2 50V cobs, etc.

if you look at a datasheet for a given chip there is a voltage current curve. heres one for a citi 1212:


heres one for a cree 3590:


so you can see that at 1400 mA the cree is less than 35V and 4 of them would be 136-140V and fit on that driver

4 of the citi 1212s are ~36.7V and would add up to 146.8V - prob no worky.(its close and meanwells have tolerance, but in general thats not a great design to be pushing components out of spec)

CobKits said:

im not sure if that answers your questions but you def should get a handle on basic electricity before attempting a diy job

http://www.allaboutcircuits.com/tex...chpt-5/what-are-series-and-parallel-circuits/

in this case "battery" = "driver" and "resistor" = "LED"

in the "series" configuration like in growmaus vids, the driver you use spits out a "constant current" , like 1400 mA or whatever. lets look at a datasheet

http://www.mouser.com/ds/2/260/HLG-185H-C-SPEC-806161.pdf

you will see for the -1400 model, the constant current region is 72-143V. so as long as your cob voltage adds up to 72-143V they will light up at 1400 mA

so you can use 3 or 4 36V cobs, 2 50V cobs, etc.

if you look at a datasheet for a given chip there is avoltage current curve. heres one for a citi 1212:
View attachment 3792144

heres one for a cree 3590:
View attachment 3792146

so you can see that at 1400 mA the cree is less than 35Vand 4 of them would be 136-140V and fit on that driver

4 of the citi 1212s are ~36.7V and would add up to 146.8V - prob no worky.(its close and meanwells have tolerance, but in general thats not a great design to be pushing components out of spec)

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Thanks I've been doing some book learning. I'm definitely lacking on the basics. Something new to learn.

so thats a series connection. note that if you put 2 citi 1212s on an hlg185h-1400b it will light up the 73.2V cob load, and the cobs dont care if there is extra voltage. voltage is only potential, current is the actual flow.

so lets look at cobs in parallel. in the case above, if we needed external dimming for some reason and we were married to a non-voltage-adjustable -B driver, then we will have hard limits on voltage. -36B is 36V, 48B is 48V, etc. (compared to the -A versions which adjust up to ~39 and ~45V respectively)

an HLG185-36b has 5.2A available (aka 5200 mA) @ 36V (https://www.trcelectronics.com/ecomm/pdf/hlg185h.pdf)

so lets pick Tc=55C on the cree curve.you can run cobs up to about 2300 MA
1 cree on a 36b would light up and run at 2300 ma where it would top out on voltage
2 cree would run at 2300 ma ea = 4600 ma where they top out on voltage
3 cree would split the 5200 mA and run at 1733 mA ea
4 cree would split the 5200 mA and run at 1300 mA ea
5 cree would split the 5200 mA and run at 1040 mA ea
etc

with the citizen, same thing albeit different because of the voltage profile. at 36V they top out at 1100mA
1 citi on a 36b would light up and run at 1100 ma where it would top out on voltage
2 citi would run at 1100 ma ea = 2200 ma where they top out on voltage
3 citi would run at 1100 ma ea = 3300 ma where they top out on voltage
4 citi would run at 1100 ma ea = 4400 ma where they top out on voltage
5 citi would split the 5200 mA and run at 1040 mA ea
6 citi would split the 5200 mA and run at 867 mA ea
etc

next lets look at a -42B driver (same datasheet https://www.trcelectronics.com/ecomm/pdf/hlg185h.pdf).

we have 4.4A available
1 cree on a 42b would light up and run at 4400 ma for a little while before it blew up (max rating on a cxb is 3600 mA)
2 cree would split the 4400 mA and run at 2200 mA ea
3 cree would split the 4400 mA and run at 1467 mA ea
4 cree would split the 4400 mA and run at 1100 mA ea
etc

BUT you see we created the dangerous situation where the driver current and voltage can exceed a single cob spec. this is why some people say parallel is "bad:" when its really poor driver selection/system design as seen above. so say you have 2 cobs running on the above setup at 2200 mA each and one gets disconnected- bye bye other cob..

had you had a -36b instead of a -42b the voltage would ahve topped out, limiting current to the cob and that wouldnt be possible

this is why i like -48A drivers with the citis. they are adjustable up to 53.5Vand run the 1818 and 1825 out to 2000-3000 mA which they can handle as they are rated for 4100 and 5700 respectively. the "A" drivers also have adjustable voltage and current so say you had a larger -42A driver like a 320 or 600 because you wanted to run a few crees out to 3000 mA (some of the drivers like the 600 have upwards of 15A!).youd simple set the voltage screw to top out at 37V and mak the system fail-safe with even 1 cob on there

and now that you understand that, go start at the beginning of this thread.

https://www.rollitup.org/t/matching-drivers-and-cobs.883866/

it should be fairly obvious how that spreadsheet at the beginning was derived. just remember when the spreadsheet shows 6.1 or 6.3 or 6.8 allowable cobs per driver - its still 6....if you can answer the question of why 6.1 is more ideal than 6.9 than you really have a good understanding of whats going on there

Thanks some how these post didn't hit my alert feed. I'll be sure to read into that thank you.

When will you have ideal citizen cob holders back in stock?