DiY LEDs - How to Power Them

[JorgeGonzales]

Actually just to add, you could just solder a single 25k resistor between the two dimming wires on the driver and run at 25% power at like 300lm/w or whatever.

 

[palmetto420]

Thanks Jorge!
Yeah, it's not really a cash thing...more of a space thing.
Thanks for the heads up on being able to dial it down to 10% with a B version! I thought I would only be able to reduce it to 50%, but I guess that's the A version only. Any recommendations on a pot?
I was going to use CPU coolers on the lights but since they'll be dialed down so much, could I possibly get away with a 6"x18" heatsink, passively cooled?

 

[PurpleBuz]

to each his own. Try a b
You've never dimmed below 50%

if you need to dim below 50% you could just turn it off.

 

[Airwalker16]

if you need to dim below 50% you could just turn it off.

Nah bro. It's good to have dimmable. At 1/3rd power on a 2100ma driver, you're throwin out 700ma of light which a lot of people use through out the entire run.

 

[PurpleBuz]

if people only use 700ma, why not use a light that's closer to that range like 1050ma instead of 2100 ? overall that's more efficient per both hardware and running costs ?

 

[RuRu.The.Half.Elf]

I posted in New to LED, What to Buy; Figure I can also try here since it is DIY I am asking about.

2x2x4 Tent, 20"x20" actual inside between the poles.

I see cutter has cxb2530 3k t2 bin for <12$. Thinking 10 of these.

Looking at Meanwell HLG-185-c500b, also @ cutter, just need a 10Kres/100Kpot for dimming?
meanwell pdf states it drives 250-500ma, 431v max.
I'm looking at 360v @.35

10 @ ~ .350 (36x.35=12.6) {12.6x10=126} [126/4=31.5]
So 126w, 31.5 theoretical watts per sqft?

I think SupraSPL stated elsewhere that 18" of 5.886 HeatsinkUSA does 60w passive. so 2x 18" and ACTIVE cooled sinks should keep nice 'n cool with fan failure saftey.

1 driver ~70$
2 Sinks ~ 40$ = 80$
10 cobs ~12$ = 120$
10 Cob holders, Fans, Aluminum angle, etc. 100$
Rough estimates with no shipping, but I gave the last parts tally a full 100$..

So >100$sqft for a long life, good (not high) efficient LED, (near) fail-safe, grow lamp.

Sound good? Can I do this better? I already own the tools, taps, sanders, wire, and much more..

 

[Airwalker16]

if people only use 700ma, why not use a light that's closer to that range like 1050ma instead of 2100 ? overall that's more efficient per both hardware and running costs ?

Why buy 2 drivers when you can have one? ;D

 

[PurpleBuz]

Why buy 2 drivers when you can have one? ;D

who said anything about two drivers?

 

[Airwalker16]

who said anything about two drivers?

You can get the performance of a 700ma driver on a Dimmable 2100. Not on an A

 

[RuRu.The.Half.Elf]

if people only use 700ma, why not use a light that's closer to that range like 1050ma instead of 2100 ? overall that's more efficient per both hardware and running costs ?

You can get the performance of a 700ma driver on a Dimmable 2100. Not on an A

I think PurpleBuz is asking why not use a cob closer to max output of 700ma.

 

[PurpleBuz]

You can get the performance of a 700ma driver on a Dimmable 2100. Not on an A

its cheaper to get a driver that fits right. its also more efficient.

I think PurpleBuz is asking why not use a cob closer to max output of 700ma.

what I meant is why not use a driver that runs at a current closer to what is desired, instead of dimming way way down ?

 

[Airwalker16]

its cheaper to get a driver that fits right. its also more efficient.


what I meant is why not use a driver that runs at a current closer to what is desired, instead of dimming way way down ?

The point is to be able to use it for seedlings to full flower.

 

[JorgeGonzales]

its cheaper to get a driver that fits right. its also more efficient.


what I meant is why not use a driver that runs at a current closer to what is desired, instead of dimming way way down ?

Because in this case he is in a small space and plans on running at 50W each eventually. So rather than buying another driver he can do it this way, and go from seed to harvest with one light.

Thanks Jorge!
Yeah, it's not really a cash thing...more of a space thing.
Thanks for the heads up on being able to dial it down to 10% with a B version! I thought I would only be able to reduce it to 50%, but I guess that's the A version only. Any recommendations on a pot?
I was going to use CPU coolers on the lights but since they'll be dialed down so much, could I possibly get away with a 6"x18" heatsink, passively cooled?

Pots are pots, just get a 25k linear Alpha or whatever brand is easy for you to get, solder lugs, for $1 or less. Or a 25k resistor would work fine if you weren't going to dim.

At 25% something like this would be fine http://www.tme.eu/en/details/rad-a6023_220/radiators/

No fans needed.

 

[JorgeGonzales]

its cheaper to get a driver that fits right. its also more efficient.


what I meant is why not use a driver that runs at a current closer to what is desired, instead of dimming way way down ?

Normally you'd be right, but he plans on starting in a small space and moving up in watts later on using the same cobs. Running at 25% he'll still be in the high 80s efficiency wise, same as any of the cheaper Meanwell's.

 

[PurpleBuz]

The point is to be able to use it for seedlings to full flower.

I understand that, but its really inefficient to run a driver under 50%. That's like running seedling under a 1K HPS, and dimming the 1K way down for a SEEDLING ?

Suggest you review the efficiency charts for a driver ? Its in every single meanwell driver datasheet.

 

[Airwalker16]

I understand that, but its really inefficient to run a driver under 50%. That's like running seedling under a 1K HPS, and dimming the 1K way down for a SEEDLING ?

Suggest you review the efficiency charts for a driver ? Its in every single meanwell driver datasheet.

Man, efficiency isn't a concern when you're talking as small of percentages as these are. We have our opinions. You keep yours, I'll keep mine.

 

[JorgeGonzales]

I understand that, but its really inefficient to run a driver under 50%. That's like running seedling under a 1K HPS, and dimming the 1K way down for a SEEDLING ?

Suggest you review the efficiency charts for a driver ? Its in every single meanwell driver datasheet.

Might want to read the post directly above this one. The one where I quoted a reasonable efficiency from that very datasheet, and gave what I consider a good reason to build this way.

The LPC he was going to buy to run two cobs temporarily maxes out at 85% efficiency, less than an HLG at 25%.

 

[Airwalker16]

Might want to read the post directly above this one. The one where I quoted a reasonable efficiency from that very datasheet, and gave what I consider a good reason to build this way.

The LPC he was going to buy to run two cobs temporarily maxes out at 85% efficiency, less than an HLG at 25%.

 

[REALSTYLES]

Man, efficiency isn't a concern when you're talking as small of percentages as these are. We have our opinions. You keep yours, I'll keep mine.

You love giving bad advice to people don't you? 2100ma is the worst advice I've seen you give and its really important that efficiency plays a role due to the fact he'll be growing in a small space. I don't think he'll like the extra heat due to poor efficiency.

 

[Airwalker16]

You love giving bad advice to people don't you? 2100ma is the worst advice I've seen you give and its really important that efficiency plays a role due to the fact he'll be growing in a small space. I don't think he'll like the extra heat due to poor efficiency.

Jeez dude.... SO HE KEEPS IT DIMMED. He could use that driver on a bigher setup later rather than buying a whole new driver.