LED expert question

[Mike Wright]

My new QB style light has a Meanwell ELG-240-48A driver, which has both voltage and wattage adjustment potentiometers. There are conflicting reports about how to dim the lights. Some say use the Vo pot and some say the Io. Originally, the vendor sent me instructions to use the Io. But my Io is stuck. So then they sent me instructions to use the Vo instead.

I'm no electrician, but I'm sure that there must be a right way to do this, in terms of producing the best light, most efficiency, etc. Can someone shed the light of their knowledge on this?

 

[Pbass]

This pleasant young sounding woman says Vo. I think I trust her! CHeers!

 

[Pbass]

I found this too so what the heck we might need it someday!

https://www.meanwell.com/Upload/PDF/ELG-240/ELG-240-SPEC.PDF

 

[Mike Wright]

Yes, PWM is a superior dimming technology, wish it was on this one. I reached out to Meanwell for the manufacturer's advice.

 

[Chris Scorpio]

Do like I do

Get the B driver and wire a dimmer on

Much much easier

 

[bluter]

My new QB style light has a Meanwell ELG-240-48A driver, which has both voltage and wattage adjustment potentiometers. There are conflicting reports about how to dim the lights. Some say use the Vo pot and some say the Io. Originally, the vendor sent me instructions to use the Io. But my Io is stuck. So then they sent me instructions to use the Vo instead.

I'm no electrician, but I'm sure that there must be a right way to do this, in terms of producing the best light, most efficiency, etc. Can someone shed the light of their knowledge on this?

are you wired series or parallel ?

Io dimming is straight dimming of the current alone with proportional dimming of the light as a result. generally more appropriate in series set ups.

Vo is not normally used for dimming. it is mainly for setting up the driver. it prevents damage to the led or cobs in parallel set ups, in the event one or more of the emitters fail. it avoids an over draw / over heat / fire scenario.

set Vo so voltage matches the desired level of your forward voltage. If one of your led strings / cobs fail the current that was passed thru that emitter would go to the others normally, possibly overloading the circuit. if you set Vo correctly this can't happen: the driver won't be able to feed more current as it is limited by voltage setting, and can't feed more current than what the led can take at that voltage.

elg drivers have more advanced dimming control and carry an added power supply for dimming , but it requires the interface. hlg drivers will only dim to 10% of power supply, elg drivers will dim to zero. hlg interface for dimming is PWM and elg uses DALI.

 

[Mike Wright]

Thanks Bluter! As it turns out, something's up with the wattage. I can't turn that pot but my board only draws 100 watts with the voltage turned all the way up (it's supposed to be 200). Back this one goes I guess.

 

[bluter]

Thanks Bluter! As it turns out, something's up with the wattage. I can't turn that pot but my board only draws 100 watts with the voltage turned all the way up (it's supposed to be 200). Back this one goes I guess.

lots of times the driver is pre - set and locked at the manufacturer as well. they purchase the driver and have the right to modify the settings. it is done a dummy control. the builder can claim the specs, but deliver less - while building a 'safe' light that won't deliver.


edit : to be certain elgs and hlgs are rock solid. they pretty much always deliver what spec on the body is.

 

[nivek]

one thing i found out very recently is these drivers are meant to be used and connected either in 'parallel' OR in 'series'.

specifically,, not your choice to decide

read the driver specifics to make sure

i had my rapid led light hooked up the opposite way it was supposed to be

for two freakin years

just recently learned of my error,, my light had been running at 1/4 power for two years,,

now i wont swear that that is true for every driver, but sure is for some

 

[Mike Wright]

Yeah, they must have tried to lock this down to 100 watts hoping a lot of people won't notice. I managed to crank it up to the rated 200 watts by really digging into the Io with a flat screwdriver and the light is HOT. No heatsinks and all aluminum so it is probably designed to get this hot, but I can see it making some people nervous.

 

[bluter]

the light is HOT. No heatsinks and all aluminum so it is probably designed to get this hot

well .... maybe


heat and dust are the enemies of all led ...

 

[The Celt]

Yeah, they must have tried to lock this down to 100 watts hoping a lot of people won't notice. I managed to crank it up to the rated 200 watts by really digging into the Io with a flat screwdriver and the light is HOT. No heatsinks and all aluminum so it is probably designed to get this hot, but I can see it making some people nervous.

If the aluminum board is getting hot, you might want to check the temperature of it. If it is running hot enough that you can not hold your hand on it, it may be too hot. Most LEDs are designed to run at 85C or lower at the junction, any hotter and it will shorten their life and may burn out

 

[Mike Wright]

I'd say it was around 60 C, the rated operating temperature of those diodes is up to 85 C. However that was with zero fans blowing on it. I figure even my one little fan will knock that down around 40 C.