Led driver, cobs and a fan?

bassman999

bassman999

Well-Known Member
Hey guys I know I have heard of this being done, but I cant find any info on how to do it.
I have a few cobs on a 700 ma driver, ad have 100V left of output for the driver, can I add a cooling fan to this circuit?
I have tied a few ways and the fan doesnt come on. The fan works fine on wall wart though.
I dont need to do this, but want to if possible to avoid another plug being used.
This is just a work light with some CXM-32 cobs and a 12V 300 ma 120mm fan
The driver is Universal Lighting everline 150 watt 700 ma driver, and wires up the same as the meanwells do even down to the pot if neded
 
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PurpleBuz

Well-Known Member
bassman999 said:
Hey guys I know I have heard of this being done, but I cant find any info on how to do it.
I have a few cobs on a 700 ma driver, ad have 100V left of output for the driver, can I add a cooling fan to this circuit?
I have tied a few ways and the fan doesnt come on. The fan works fine on wall wart though.
I dont need to do this, but want to if possible to avoid another plug being used.
This is just a work light with some CXM-32 cobs and a 12V 300 ma 120mm fan
The driver is Universal Lighting everline 150 watt 700 ma driver, and wires up the same as the meanwells do even down to the pot if neded
Click to expand...
you need a dc to dc buck driver to drive a fan off of a constant current driver.

something similar to this one

upload_2016-2-8_10-54-48.png
http://www.amazon.com/gp/product/B0179GJEDQ?psc=1&redirect=true&ref_=ox_sc_sfl_title_2&smid=A2OCOGC9B25845
 
bassman999

bassman999

Well-Known Member
The fan I am running can tolerate 1amp of current, its a server papst fan, I dont think the other fan I was going to use would like that current
 
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PurpleBuz

Well-Known Member
bassman999 said:
The fan I am running can tolerate 1amp of current, its a server papst fan, I dont think the other fan I was going to use would like that current
Click to expand...
that makes sense, put a tester on the fan and see what current its getting if you want to verify. I think the buck driver is safer since its constant voltage.
 
GVMV

GVMV

Active Member
You can do it with a Zenier Diode, google it.It is a way to get differing voltages for small loads inside a circuit you are making.
 
bassman999

bassman999

Well-Known Member
Im no sure why, bu the fan is only pulling 8V, which is actually optimal, but I dont know why thats what its getting?!?
 
bassman999

bassman999

Well-Known Member
GVMV said:
You can do it with a Zenier Diode, google it.It is a way to get differing voltages for small loads inside a circuit you are making.
Click to expand...
I remember watching an Indian lady teach a class on this, made into a youtube video.
 
bassman999

bassman999

Well-Known Member
bassman999 said:
Since V is lower than I thought I will try to measure the current the fan is disipating
Click to expand...
Im either doing it wrong, or the current exceeds my DMM range as it states on DMM screen.
Ill just power the fan seperately till I understand the circuit better
 
Abiqua

Abiqua

Well-Known Member
bassman999 said:
Im no sure why, bu the fan is only pulling 8V, which is actually optimal, but I dont know why thats what its getting?!?
Click to expand...
How much current is it pulling?

You are essentially running a constant voltage device on a constant current driver....voltage most likely isn't constant and hence only 8v's, but that means that current is reduced too, but you have a cf of sorts :peace:
 
bassman999

bassman999

Well-Known Member
Abiqua said:
How much current is it pulling?

You are essentially running a constant voltage device on a constant current driver....voltage most likely isn't constant and hence only 8v's, but that means that current is reduced too, but you have a cf of sorts :peace:
Click to expand...
Im not sure how to measure current draw from the fan.
I thought it was use the DMM set to DC current, and put the DMM in series with the fan, but that didnt work.
Maybe I should power the fan with the cobs out of the circuit?
 
Airwalker16

Airwalker16

Well-Known Member
Why don't you just buy a meanwell apv12-12? They wire right into your wall plug with your driver(s) and have 1amp of current at 12v's. They also have 12-18,12-24. But they're all only like $5-$7..
 
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