Cob help

Randomblame said:

Hey Molloy!
A HLG-240H-C700 delivers up to 357vdc at 700mA and is able to drive 10 CLU048-1212C4(5. and 6. gen.) in series at ~25w.
Better take the 1400mA version to drive your 5 COB setup or buy another 5 1212's to rise system effiency above 50%.

BTW,
the file below is Meanwell's datasheet for HLG-240 drivers..

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Molloy said:

I was wanting to,run them at 50w

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Randomblame said:

You need a driver with 1,4A (36v x 1,4A= ~50w) with enough voltage to drive 5 CLU048-1212 in series (5x ~36v =~180v + a few volts of headroom)
A gen.5 1212 needs 36,1v @50°C and 1,4A, so you need at least 180,5v
A gen.6 1212 with better effiency only needs 35,6v @50° and 1,4A, so 5 will only need 178v.(estimated f. datasheet)

A HLG-240H-C1400 can deliver only 179v@1,4A. That's normally enough for 5 gen.6 1212 but not for gen.5.

But I'm pretty sure the driver will work with both setups because Meanwell drivers have some protection circuits.
If the voltage is a "bit" too high, it reduces the current in turn as long as it runs within the specifications.
Over voltage protection is only triggered between 188 and 206v(for HLG-240H-C1400), that means, as long as you stay under 188v, it will run.
The only thing you may notice is that you see a small "flicker" when you turn up the lamp over ~95-97% and it internally changes its circuit, which results then in no increase between 97 and 100%.

So with gen.5 you will probably never get the full 1400mA for the LED's, but maybe 1380mA ..
The whole thing gets worse when the LED's run cold and better when they get warmer.
At 85°C Tj. you can easily use both generations with no bad exspectations!

My recommendation, take the next larger driver in this case an HLG-320H-C1400. This gives you enough voltage and has enough headroom to upgrade later. This is maybe a bit overkill but you are allways on the safe side.

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