LEDgardener

I'm building my DIY COB LED. With:

4x BXRC-35E10K0-B-73-SE (50V)
1x MW ELG-240-C1050 (239.4W, 114-228V, 1,05A)
4x Alpine 64 Plus heatsink + fan (12V 0.25A).
2x Arctic F8 fans (12V 0.24A) for a breeze over the grow area.

Now I want to wire the fans to the ELG driver but I don't know how (easy/cheap). In a perfect situation I can dim the fans on the heatsink and dim the remote fans.

If it gives to much problems with the CC driver I think I can find an old charger/driver with 12V and 2A

Anyone got some advice?

I'm sorry man because I won't have no advice to tell you on how to wire the fans directly on your led driver because I did my light too and used arctic 64plus but i use meanwell apv 12 -xx in order to power my fans

I wasn't too comfortable in the idea of using an old 12V charger sounded too unsecured for my precious cobs ^^

I guess you could parallel 4 of your fans together and wire the group in series with the rest of the stuff on your driver if you really wanted to. I'd suggest just getting a different power supply though like the one you mentioned. Something 12V will be very easy to find.

Personally I would run a small 12v driver for the fans.

Paralleling up those CPU fans in a high voltage CC circuit is asking for trouble.

Guessing you'd want the circulation fans on constantly too? Two drivers make this easier.

alreaaaa wrote: ↑

Mon Feb 26, 2018 10:11 pm

I'm sorry man because I won't have no advice to tell you on how to wire the fans directly on your led driver because I did my light too and used arctic 64plus but i use meanwell apv 12 -xx in order to power my fans

I wasn't too comfortable in the idea of using an old 12V charger sounded too unsecured for my precious cobs ^^

Weighing out all my options, might need a new one after all.

LEDG wrote: ↑

Tue Feb 27, 2018 1:39 am

I guess you could parallel 4 of your fans together and wire the group in series with the rest of the stuff on your driver if you really wanted to. I'd suggest just getting a different power supply though like the one you mentioned. Something 12V will be very easy to find.

Ah didn't thought of that one, the driver can handle the extra 12V, but i'm wondering what the fans will do If i wire the 4 fans of the heatsinks to the ELG, they get 1.05/4=0.26A, more then the 0.25A that it runs on.
Will they spin faster or just die? Is it possible to lower the amp with a resistor?
Will they equally reduce speed when I dim the driver with the 100Ω potentiometer?

If i buy an extra driver for the fans, is it better to take a constant voltage or constant current? I want to be able to dim the heatsink group fans (4) and the breeze group (2) separately.

Edit:

Kiwi_Jezza wrote: ↑

Tue Feb 27, 2018 8:23 am

Personally I would run a small 12v driver for the fans.

Paralleling up those CPU fans in a high voltage CC circuit is asking for trouble.

Guessing you'd want the circulation fans on constantly too? Two drivers make this easier.

I just need a new driver for the fans. Don't want to burn the COB's. Is it better to take a constant voltage or constant current? I want to be able to dim the heatsink group fans (4) and the breeze group (2) separately.

So I downloaded an circuit simulator and tried to schematize my thoughts. If I add an resistor 240Ω in serie with the 4 fans I can reduce the amps through the fans to 0.25A.

Don't know if this works but it looks nice.
I've added the other circuit for the other 2 fans separate at the top. Couldn't add potentiometer with this free trial.

So when you dim your lights, your fans will spin down too - is that what you want?

LEDG wrote: ↑

Thu Mar 01, 2018 1:22 am

So when you dim your lights, your fans will spin down too - is that what you want?

That was the idea. But don't think I'll connect them in that way.

But now just hypothetical: What if i connect them in that way?
The heatsinks w/ fans are designed to remove up to 90W of heat.¹ The COB, running at 50W² will produce like what? 25W of heat if 50% efficient, with the fans blowing max speed (2000RPM) and the heatsinks being able to remove 90W should keep them low. 90W>25W
If i dim the fans (1000 RPM) and the heatsink only remove half the heat, 45 heatwatt and the COBs consume only 25W, generating 12 heatwatt (if efficiency is 50%), the cooling should be more then enough 45W>12.5W

My concerns are in the dimming, in this simulation i give them a fixed resistance, but if the current changes, the resistance changes with them. (Voltage almost stays the same 48-49V, current halves to 0.525A R=U/I, the resistance of the COB almost doubles) So don't know how the fans will behave in that situation.

If I dim the driver maximum to 0.53A how will the fans react with that 240Ω in parallel?
Will they get 0,13A at 6V each if resistance stays the same or
will they get like 0.12A at 12V if voltage stays the same and resistance increase. I just don't know.
Reduce the fans speed lineair if dimming the current and is there is a threshold for the fans when they start/stop working? It says the working speed is 600 - 2,000 RPM (Controlled by PWM).
Big con, if one fan breaks down and the current is split among the other fans, they'll all die and the COB's with them.

In short, just to much uncertainty to wire like this. But sounded like a good plan.


¹Max. Cooling Capacity: 100 Watts
Recommended for TDP up to: 90 Watts
https://www.arctic.ac/eu_en/alpine-64-plus.html

²BXRC-35E10K0-B-73-SE (~50V) at 1.05A = ~52.5W
https://www.bridgelux.com/sites/default ... %20G_0.pdf
http://www.meanwell.com/webapp/product/ ... =ELG-240-C

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Maxxor wrote: ↑

Fri Mar 02, 2018 6:39 am

A 12 volt 1 watt power supply is the simple, inexpensive solution to power your fans. If you wanted to slow them down due to noise, you could either under-power them w/ a lower voltage transformer or buy Noctua fans, which come with low noise resistor cables. My Noctuas are so quiet that I run them @ 12 volts constantly. They use a negligible amount of electricity.

Did you mean 1A @ 12V?

Also, if you're concerned with a cheap 12VDC PS crapping-out, have you already looked at and dismissed the MW SCW05B-12 for some reason? It's the perfect way to power fans by piggy-backing off your main driver/PSU.



You supply 36V (18-36VDC), it puts out 12V.

The "C" version bucks higher voltage DC (36-72V) to 12V also.