JorgeGonzales
Well-Known Member
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.
DiY LEDs - How to Power Them
- Thread starter SupraSPL
- Start date
palmetto420
Member
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?
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?
if you need to dim below 50% you could just turn it off.
Airwalker16
Well-Known Member
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.
RuRu.The.Half.Elf
Well-Known Member
I posted in New to LED, What to Buy; Figure I can also try here since it is DIY I am asking about.
Airwalker16
Well-Known Member
Why buy 2 drivers when you can have one? ;D
who said anything about two drivers?
Airwalker16
Well-Known Member
You can get the performance of a 700ma driver on a Dimmable 2100. Not on an A
RuRu.The.Half.Elf
Well-Known Member
I think PurpleBuz is asking why not use a cob closer to max output of 700ma.
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 ?
Airwalker16
Well-Known Member
The point is to be able to use it for seedlings to full flower.
JorgeGonzales
Well-Known Member
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.
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
Well-Known Member
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.
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
Well-Known Member
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
Well-Known Member
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%.
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Airwalker16
Well-Known Member
REALSTYLES
Well-Known Member
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
Well-Known Member
Jeez dude.... SO HE KEEPS IT DIMMED. He could use that driver on a bigher setup later rather than buying a whole new driver.