LEDgardener

Hi everyone,
After 15 years of growing under hps i'm thinking about catching up with technology and swiching to cob. i'm aiming to find a suitble replacment (ppfd wise) that will be more eficiente and decrease power consumption and heat whithout crossing the 100$ limit.
My thoughts after a little bit of reserch:
Single cob builed
Luminus cxm 32 35 80 54 cob
Lpc 150 1750 to drive it
Whith active heatsink and 80deg lense.

Sounds reasonable to anyone?

I appologise for the horrible english...please try to look beond...

Thanks...

Duvdev wrote: ↑

Mon Jun 04, 2018 1:15 pm

Hi everyone,
After 15 years of growing under hps i'm thinking about catching up with technology and swiching to cob. i'm aiming to find a suitble replacment (ppfd wise) that will be more eficiente and decrease power consumption and heat whithout crossing the 100$ limit.
My thoughts after a little bit of reserch:
Single cob builed
Luminus cxm 32 35 80 54 cob
Lpc 150 1750 to drive it
Whith active heatsink and 80deg lense.

Sounds reasonable to anyone?

I appologise for the horrible english...please try to look beond...

Thanks...

welcome to the forum

that's a cxm gen 3 3500k CCT cob correct? your close to being perfect on you matching parts...

but I would jump up to a lpc-150-2800.. the 51v is kind of on the lower voltage range of the 1750 driver...( 43v-86v) the driver won't be as efficient... with the 2800 your right near the max of the voltage range ( 27-54v) you'll be using max driver efficiency and your single cob would put out roughly 142w ( 2.8 ma x 51v = 142.8w) and that's only running the cob at roughly 62% of max power... the 1750 would only run roughly 90w ( 1.75a x 51v = 89.25w)

also with cobs being a little lower efficacy than the lm561c or lm301b, you will need a little more than half the wattage to equal light output of the 250 hps.. 150 ish watts is about perfect.

again welcome and don't worry about broken English. we can work our way thru it

Hi jgg
Thank you for your time energy and for the super fast reply!
Happy to hear i'm not far off.
A few questions if i may...:

You reffered to the cxm32 as a 51v, but on the specs it's 54v(Vf)...am i missing something?
That was the reason for thinking about the lpc150 1750 ,it seemed like a too tight fit..but thats just an intuitive presumption..
The specs also indicate that its 2.64A(If)

https://www.mouser.co.il/ProductDetail/ ... mfwaUPI%3d

So i'm a bit baffled...(is that a made up word? )
I got the impression that it's better to run the cob on a low current for higher efficasy and longer life span...

The main inspiration was the"migro 100" that cought my eye, i tried to figure out what kind of cob it uses. The migro driver is a cc 1750ma but the v is 63-116...the specs say 107w...meaning a 72v cob underdrived?

Anyway...the wizard has spoken...2800 it is.

Thank's again...

Duvdev wrote: ↑

Mon Jun 04, 2018 7:35 pm

Hi jgg
Thank you for your time energy and for the super fast reply!
Happy to hear i'm not far off.
A few questions if i may...:

You reffered to the cxm32 as a 51v, but on the specs it's 54v(Vf)...am i missing something?
That was the reason for thinking about the lpc150 1750 ,it seemed like a too tight fit..but thats just an intuitive presumption..
The specs also indicate that its 2.64A(If)

https://www.mouser.co.il/ProductDetail/ ... mfwaUPI%3d

So i'm a bit baffled...(is that a made up word? )
I got the impression that it's better to run the cob on a low current for higher efficasy and longer life span...

The main inspiration was the"migro 100" that cought my eye, i tried to figure out what kind of cob it uses. The migro driver is a cc 1750ma but the v is 63-116...the specs say 107w...meaning a 72v cob underdrived?

Anyway...the wizard has spoken...2800 it is.

Thank's again...

good thing you gave the link.. I've noticed the difference... I was look at gen 3 numbers
https://www.digikey.com/product-detail/ ... ND/6151715

and your talking just cxm32's after looking at the data sheet... it shows typical numbers as 2667 some odd ma at 52.5v. for 140w.. that lpc 1500-2800 would still be my choice for drivers..

yes technically it's called a 54v cob.. but that's the upper end of max power... my quantum boards are 54v also.. but they only run roughly 51 volts at the current I'm giving them..

also yes technically you do want to run cobs and boards softer.. but you get to budget constraints.. running cobs super soft requires more cobs... instead of one cob running around 70-75% at 140ish watts for the replacing the 250w hps... your going to need 2 or 3 really softly driven cobs to equal the Amount of light.. stay below 75% of max with proper cooling is normally good... running your cob at 2800ma ( or the typical 2667ma) puts you right at 70% ( 68%) if you were to run 1750 you would be at 44%... and would need at lease 2 cxm's.

to your migro question... yes.. if it's a 72v cob it's really being ran soft... normally bigger voltage means more current capable... also with the drivers voltage range.. the driver is not as efficient as it could be... you always want to be as close as you can ( with in a few volts) to the max end of the range.. the driver will be to the efficiency % listed ( my hlg is 95% and I'm right on that 54v cusp)

one thing also to double check, is if that actively cooled heat sink can handle 140-150w easy

I love how Ledgardener made the top tier "wizard" it just means I posted a lot!

Hi jgg,
Thank you for the gen3 link, that's the the one i was actualy looking for...thow i see it's not sold in singles yet...i guesse i can wait ...its numbers are better( looks like it will run cooler )but it's going to b a serios workout for my gratification delaying capabilities.

As for the heatsink, how hot are we talking? I plan on readjusting the hps's inline cooling fan to fit the new light, but any insight regarding the heatsink will be great...

Thanks again
Figgured your not a self titled wizard, thats why it fits...

Duvdev wrote: ↑

Tue Jun 05, 2018 9:21 am

Hi jgg,
Thank you for the gen3 link, that's the the one i was actualy looking for...thow i see it's not sold in singles yet...i guesse i can wait ...its numbers are better( looks like it will run cooler )but it's going to b a serios workout for my gratification delaying capabilities.

As for the heatsink, how hot are we talking? I plan on readjusting the hps's inline cooling fan to fit the new light, but any insight regarding the heatsink will be great...

Thanks again
Figgured your not a self titled wizard, thats why it fits...

they do sell singles at digikey for the cxm32's .. they just out of stock atm.. so it says you got to buy the whole 300 lot

got a link to the heat sink you were thinking about? yes having your hps fan move air across will also will help... how much extra heat you would need to move depends on how well and how much the heat sink can do on it's own... typical case temp the gen3 is 85C so heat sink has to be able to keep it around or lower than that.

a good read on how to figure out heat sinks from our awesome host Ledgardener
http://ledgardener.com/find-heat-sink-cob/

Hi jgg and thanks again...

So, after some additional e-probing i've come to realize that going whith the 1 cob/100$ build is not the opimal route...after discovering HLG 135 v2kit (made me drool a little), i found it hard to go back to the cob concept. However, all options are still on the table...

140ish 1 cob config
Parts so far:
Cxm32 35 80 54 -38$(without shpmnt)
Lpc 150-2800 -35$( " " )
Heat sink
100mm x 120mm -17.5$-35$(incld shpmnt )
(Heatsink link 1) https://m.aliexpress.com/item/324852505 ... b-led-chip

(Heatsink link2)
https://m.aliexpress.com/item/328237533 ... form=msite

Wire, led holder, thermal paste...15$~

...already over 100$ ,and with shipping costs for the cob and the driver can reach 150 and higher...

well...as a good friend of mine once said:" you cant buy a dollar with 80 cents..."

And from another angle...how long will the cob last (under such stress)before starting to dimm...also an importent parameter...

Hav'nt given up yet

haha 135w qb v2 kit made ya drool

in all honesty I would go qb kit.. I'm a qb nut and always recommend them for a first build.. out of the shear ease of putting it together.. along with them giving you everything you need right in the kit.. your in EU correct?

https://www.todogrowled.com/es/17-hlg-quantum-boards is the distributor in Spain. The U.K. distributor I think only has 300/550's

Cob build... I would go with the first heat sink link.. seeing how your going to be near max wattage range, make sure you get the hps fan on it for extra protection.. or if you have a old computer fan + dc wall dongle laying around, hook it up mounted right to the heat sink. extra air movement is never a bad thing. .

the Cob should run its full expect lifetime since the 2800 is pretty much typical/test current( 2668ma) only things that could change it is not 100% thermal pasted down.. or the heat sink not displacing heat as it should. hence why extra air always a good thing

either the cob build or the 135w qb v1/v2 kit will replace the 250w hps. I'm guessing after tax+shipping both options will be within 20-30 USD from each other... the qb kit will be easier and will give you a better lum/w rating ( efficacy ) ...

Here's another vote for the QB kit

Ha, eu...israel is considered eu only when it comes to basketball or eurovision song contest
The desirble 135 kit+tax+shipping (from spain) is 250€...(295$).
Cuold be better but Actualy not so bad, considering the tons of non fuctional lights ,at even higher prices, on the market.

Hi ledg, thank you for this highly extensive, interesting and fun platform..learnd alot here!

Jgg- thanks for the spanish link...from some reason amazon does'nt ship the 135 to israel,
The 65 and 100 it does...