I'm looking to buy a LRS-350-36 for my project to feed 5x50W LED at 30-34v Vf 1750mA (https://www.aliexpress.com/item/32867490711.html). This PS use a 1U form factor that I must have due space constraints. My question is: can I drop 4V using the adj. pot and have a output of 32V without problem or affect PS performance? Is there any downside of such drop? Another thing that datasheet is lacking is that ajustment range, anyone know the up/down limits?
I was able to adjust such 12V supplies down to about 10.5V, which means that you are likely to get as low as 31.5V or 32V minimum.
Here is an actual datasheet for your supply:
It states that you can adjust the 36V version from 32.4V to 39.6V, but I think that the actual range is just a little bit wider (because the range they specify is guaranteed, but the actual one is usually beyond that).
Lowering this power supply's voltage to its minimum adjustable value should have no negative consequences because it was designed for that.
However, I would recommend that you use a constant current source instead of a constant voltage, since an LED current varies greatly over a very small voltage change. You need to somehow protect the LEDs from too much current. It is better to under-power them instead of over-powering.
Personally, I tend to drive LEDs at no more than half of their rated power; the lower the power applied, the longer they last, which is especially true with cheap Chinese LEDs. Most LED lights manufacturers do the opposite and drive LEDs with 2-3 times their rated power (to save money on LEDs), and that's why they don't last that long. Heat is another issue, as most LED lights have too much heat produced in too little space with no means of dissipating it sufficiently.
- Forward Voltage: 30-35V
- Forward Current: 30W:1050mA,50W:1750mA 100W:3500mA
Note: voltage is given as a range while current is a fixed value.
These LEDs need a fixed current (or current limited supply) attempting to use them with a fixed voltage supply will not work well.
get a LED power supply.