Lighting Sizing drivers, Series vs paralell - by BigSm0

[BigSm0]

Well jello there friends...Brand new very first post. I'm old school, and have been just blown away with Mephisto Autos and COBs, quite a long way away from picking a bulb and a hood for a HPS light like it used to be. So I have been trying to get to the bottom of all this. I currently have three 50v CLU048-1818s 90cri 2 x 3500k - 1 x 3000k...Here is my dilemma, what the hell Mean Well driver should I use? I wouldn't mind getting another 3000k 1818 if its appropriate. The whole thing is in a 3x2 area. I literally stole the cheap ass drivers out of a blurple module and cobbled (pun intended) this together with 3 crap drivers. Now its time for a real driver. So what to do? I have been making my brain smoke with all these crazy formulas and forward voltages and series/parallel, constant current v. constant voltage, reflectors and lenses? I would like to have them be the best they can be. HELP!!!!!


P.S. Anybody know where to get a heatsink like the one in that picture?

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You can try heatsink USA for the heatsink. I dot think they have that specific one but close. As for which driver I realized that a lot of the guys I gave help to without an explanation came back asking for help on their next light. Which is fine but it's better to understand what you are doing right? No crazy calculations here.


If you read this twice you will get it. It's hard at first but very simple in the end and you will be happy you understand it.

The first part is figuring the forward voltage you need for the driver.
Total number of cobs multiplied by the cobs voltage.
The 1818 chart is below. 50v to make it simple. If you choose 3 cobs that's 3x50=150 fv

Now the next part you need to answer yourself. Knowing the cob is 50v you now have to choose a current. The wattage is nothing more than the voltage(50) multiplied by the current.

Drivers have very basic numbers 750ma, 1050ma, 1400ma
So voltage X current.
50x7.50 -37.5 watts
50x1.05 -52.5 watts.
50x1.4 -70 watts

To sum it all up.
If you wanted 3 cobs at 50 watts you would need a 150fv driver (3x50). with a current of 1050ma. (50x1050).

If you like I can write it down and take a picture? Might be easier this way too.

 

[wwwillie]

Wow, thanks @BigSm0 you laid that out nicely.
I have a question though. It seems things never add up when you go to spec these things as I am sure everyone has encountered. Just how does it work when you have left over voltage? You know, when you add the forward voltage of the COBs you are using and you have "volts" left over. IE: you have a driver that has 150 volts to drive with and you have 3 COBs with a VF of 42v so 3x42=126 and that leaves 24 volts "left over" What about these excess volts and how much can be safely left over? Can I run one COB? two? It's been puzzling me for a while.

@Dr.Bubbles Heatsink USA is an excellent outfit. I buy all my power amplifier heat sinks there.

 

[Dr.Bubbles]

@BigSm0 Thanks, I think I got it money now....I was getting VERY frustrated, as I have always been sort of a pro with wiring and electricity. I went to car stereo/alarm trade school, my dad was a residential/commercial alarm installer for 35 years, I wired my last grow room with a 80a sub panel wired off the main breaker box with GFI outlets, and have been series and parallel wiring subwoofers and guitar speakers for ages getting the ohms where they need to be for an amplifier or to play with other speakers. Here is a question though....What do u recommend, Constant Current driver or Constant Voltage driver. I'm leaning toward the CC variety. Thanks for the help. @wwwillie ....Good question bro....this shit is not as straightforward as it could be. Cheers....R5

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[xxBALLINxx]

You can try heatsink USA for the heatsink. I dot think they have that specific one but close. As for which driver I realized that a lot of the guys I gave help to without an explanation came back asking for help on their next light. Which is fine but it's better to understand what you are doing right? No crazy calculations here.


If you read this twice you will get it. It's hard at first but very simple in the end and you will be happy you understand it.

The first part is figuring the forward voltage you need for the driver.
Total number of cobs multiplied by the cobs voltage.
The 1818 chart is below. 50v to make it simple. If you choose 3 cobs that's 3x50=150 fv

Now the next part you need to answer yourself. Knowing the cob is 50v you now have to choose a current. The wattage is nothing more than the voltage(50) multiplied by the current.

Drivers have very basic numbers 750ma, 1050ma, 1400ma
So voltage X current.
50x7.50 -37.5 watts
50x1.05 -52.5 watts.
50x1.4 -70 watts

To sum it all up.
If you wanted 3 cobs at 50 watts you would need a 150fv driver (3x50). with a current of 1050ma. (50x1050).

View attachment 779490

If you like I can write it down and take a picture? Might be easier this way too.

Hey smo are you still selling cobs and. If so how many would it take to fill 3x8 room

https://www.autoflower.org/index.php?threads/60787/

 

[BigSm0]

Hey smo are you still selling cobs and. If so how many would it take to fill 3x8 room

https://www.autoflower.org/index.php?threads/60787/

Yes sir. No plans otherwise. Cobs, partially built lights and complete lights. Plenty of new stock too, built and tested.

 

[pop22]

Get the best of both. Drivers like the HLG240H-C1750 are both constant current and constant voltage.

@BigSm0 Thanks, I think I got it money now....I was getting VERY frustrated, as I have always been sort of a pro with wiring and electricity. I went to car stereo/alarm trade school, my dad was a residential/commercial alarm installer for 35 years, I wired my last grow room with a 80a sub panel wired off the main breaker box with GFI outlets, and have been series and parallel wiring subwoofers and guitar speakers for ages getting the ohms where they need to be for an amplifier or to play with other speakers. Here is a question though....What do u recommend, Constant Current driver or Constant Voltage driver. I'm leaning toward the CC variety. Thanks for the help. @wwwillie ....Good question bro....this shit is not as straightforward as it could be. Cheers....R5

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[pop22]

"leftover voltage" is simply unused headroom. You can use any number of cobs in series the fit withing the minimum and maximum voltage. Many Meanwell driver have a little extra headroom and you can squeeze in an extra cob if you aren't over the maximum rated by more than a few volts. However, the down side of series wiring is being limited in max voltage by the cobholder's voltage rating, which is to prevent possible shorting. I believe Ideal cob holders are rated to 250V and the BJB holders are 150V max.

Wow, thanks @BigSm0 you laid that out nicely.
I have a question though. It seems things never add up when you go to spec these things as I am sure everyone has encountered. Just how does it work when you have left over voltage? You know, when you add the forward voltage of the COBs you are using and you have "volts" left over. IE: you have a driver that has 150 volts to drive with and you have 3 COBs with a VF of 42v so 3x42=126 and that leaves 24 volts "left over" What about these excess volts and how much can be safely left over? Can I run one COB? two? It's been puzzling me for a while.

@Dr.Bubbles Heatsink USA is an excellent outfit. I buy all my power amplifier heat sinks there.

 

[Dr.Bubbles]

"leftover voltage" is simply unused headroom. You can use any number of cobs in series the fit withing the minimum and maximum voltage. Many Meanwell driver have a little extra headroom and you can squeeze in an extra cob if you aren't over the maximum rated by more than a few volts. However, the down side of series wiring is being limited in max voltage by the cobholder's voltage rating, which is to prevent possible shorting. I believe Ideal cob holders are rated to 250V and the BJB holders are 150V max.

I just got the HLG-240H-C1050B running four 1818s in series. I just got the driver on Wednesday night....WOW....What a difference from the no name 600ma Chinese junk. My very first Meanie!! I will be grabbing the 320 version as well. I now have a KICK ass light setup...Just in time for my AvT and Livers N Cheese. Just finished my very first Autos....Three Walter White phistos that showed two very distinct phenos. The two I'm assuming are rock solid Walter...But the other one is like a more spindley and lanky girl that screams old school Northern Lights. Very strong Northern aroma. Just harvested two about 2 hours ago and got one more coming in 2 or 3 days. I picked these a day or two early, because I love the super quality of the genetics when the trichomes are just milky. Such an uplifting high rather than couch lock.

I have to assume I have the most MacGyvered light on AFN...Or close to it. All my cobs are on one circuit, but they are all on different pieces and parts that I stole from other places. One is on a 133mm anodized pin fin...Which is on a freaking gooseneck!!!!! Another one is an tiny heatsink with a fan....On ANOTHER gooseneck, and the last two are on a slab of heatsink.....With fans. I turned an old car stereo amp chassis into the standoff to mount my potentiometer for my 240 Meanie. Works great. The true spirit of DIY is scrounging as much as building!! Good luck to all the true diy COB guys!!!!!!! Peace

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[pop22]

Thats why they call it DIY! As we used to say in racing: Run what ya brung!

I just got the HLG-240H-C1050B running four 1818s in series. I just got the driver on Wednesday night....WOW....What a difference from the no name 600ma Chinese junk. My very first Meanie!! I will be grabbing the 320 version as well. I now have a KICK ass light setup...Just in time for my AvT and Livers N Cheese. Just finished my very first Autos....Three Walter White phistos that showed two very distinct phenos. The two I'm assuming are rock solid Walter...But the other one is like a more spindley and lanky girl that screams old school Northern Lights. Very strong Northern aroma. Just harvested two about 2 hours ago and got one more coming in 2 or 3 days. I picked these a day or two early, because I love the super quality of the genetics when the trichomes are just milky. Such an uplifting high rather than couch lock.

I have to assume I have the most MacGyvered light on AFN...Or close to it. All my cobs are on one circuit, but they are all on different pieces and parts that I stole from other places. One is on a 133mm anodized pin fin...Which is on a freaking gooseneck!!!!! Another one is an tiny heatsink with a fan....On ANOTHER gooseneck, and the last two are on a slab of heatsink.....With fans. I turned an old car stereo amp chassis into the standoff to mount my potentiometer for my 240 Meanie. Works great. The true spirit of DIY is scrounging as much as building!! Good luck to all the true diy COB guys!!!!!!! Peace

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[Dr.Bubbles]

Some DIY. I used to run my Fox body 5.0 down at the track. Run what ya bring heads up.

Me and the misses went blueberry picking on Tuesday afternoon and made a badass scratch blueberry crunch pie. 4.5# on the scale.

Walter White pic from 2 or 3 days ago

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