Dimmed high current driver vs lower current one

[teru]

Hi everyone! I'm new here and about to start my first COB build. There is a lot of info to assimilate for a newbie, but I'm doing my best
I can't seem to find straight answers to a few questions regarding dimming the COB drivers (lets consider Mean Well hlg-c ones). I will present them in a form of a list.

1) Is running a 2800 mA driver dimmed to 1400 mA the same as running a 1400 mA not dimmed (at max current)? If not, what are the differences?

2) Is the built in dimming feature of the A series driver in any way better than having a separate potentiometer connected to a B series driver? (except for the difference in the dimming range 10-100% vs 50-100%) Say, a 2800 mA driver with a potentiometer set to 50% vs the equivalente driver with its dimmer setall the way down to 1400mA?

I want to put together a simple build:
5 cxb3950 with HLG-240H-C1400A. I would like to be able to adjust the ligth output depending on grow area or palnts needs, without losing much quality.

I hope I have managed to state the issue clearly, please pardon any errors! Lookig forward to reading your answers!

[Kiwi_Jezza]

To dim a driver normally means a slight loss in efficiency as the load decreases. Meanwell HLG's are VERY efficient but do run most efficiently at full; or close to full load. I'm not entirely sure I understand your question re: current otherwise. 2800mA is outside the efficacy range of those Cree's you mentioned and 95% of other cobs too. Even if the rated max is 3.6 or 4.2, there is no efficiency to be had up there, just heat. A 1400mA driver is infinitely more usable for our purposes.

A-type drivers have a slightly higher output when compared with B-type drivers. That said, B-type is nice being able to have the dimmer more accessible, or even mounted remotely from the leads. It also effects the IP rating of it.

I have both. No preference. Just different.

[teru]

Thanks for your answer, Kiwi.

2800mA is outside the efficacy range of those Cree's you mentioned and 95% of other cobs too.

Oh, O get it. I guess I misinterpreted the relative luminus flux graph from the cxb3590 data sheet:

See how in the example they calculate lumens output at 2800 mA? That part confused me. Anyway, I should have been more clear and focused more on describing of what actually I am trying to achieve.

So, as I said, 5 cxb3590 with a 1400mA series A driver run at 1400mA should give me about 39k lm (7800 lm x 5). However, this is likely too much for my current area of 4.5 feet (don't want light burns). That's why I plan on running the driver at 700 mA, which is the driver's minimum, first, and then see if later the plants are comfortable with slightly higher value. However, as you can see above, 700 mA lies outside of the graph provided in the data sheet, so I have no way of knowing the lumens I will get at 700 mA (about half that much?), nor if and how much the light quality will diminish at this point. Maybe it will no longer be usable for growing (because of the spectrum changes)? That's what don't know.

In future I want to be able to use bigger area while still using the same leds (that's when I will turn the knob on the driver way up).

[teru]

Bump. Anyone?

[LEDG]

Unfortunately Cree doesn’t provide any data below 1400mA that I’ve seen. Not even in their product characterization tool.

I can tell you this: my first build used 4x Cree CXB3590 at 1400mA in a 2x2 and my plants did really well. That was a very popular rig back in the day for a 2x2. Dimming to 700mA will be a good idea for early stages of growth and you can increase from there.

[teru]

Thanks for the reference, now I feel more confident about buying the stuff for my intended build.