Matching Drivers and COBs

alesh said:
Yeah I knitw the town where they're made. It's got a nice nuance on this forum as the town's name (Hulin) could be translated into English as a "town where people smoke weed" :)
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Bonjour
You forget to mention ice wine...!
One of my favorite...Austrian wine are so good too..and It is a french who say that...lol!
CU
 
satdom said:
Can you run drivers in series? It seems as if you should be able too.

By running 4 of these I should have plenty of voltage (44V) to run this clearance LED at very high efficiency (above 50%???) @300ma

https://m.fasttech.com/products/0/10008079/1714101-1-3-1w-85-277v-3w-high-power-constant-current-led

http://www.newark.com/cree/cxa2520-0000-000n00q230f/led-hb-white-2379lm-screw/dp/44W6075

I care more about the led efficiency than the driver, as the heat sink has to remove the led heat.
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Drivers cannot be connected together in any way.
 
bassman999 said:
Cobs can definitely be ran in series, which driver did you have in mind to use, or are you asking what driver to choose?
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he asked about running drivers in series not cobs .....

I have seen drivers run in parallel on many of the cheap Chinese cob lights. apparently they are overstocked in 500ma drivers. They do not seem to deliver what they promised (per their specs). never seen drivers run in series.
 
PurpleBuz said:
he asked about running drivers in series not cobs .....

I have seen drivers run in parallel on many of the cheap Chinese cob lights. apparently they are overstocked in 500ma drivers. They do not seem to deliver what they promised (per their specs). never seen drivers run in series.
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Parallel I could see but series..... I'm thinking not such a good idea.
 
PurpleBuz said:
he asked about running drivers in series not cobs .....

I have seen drivers run in parallel on many of the cheap Chinese cob lights. apparently they are overstocked in 500ma drivers. They do not seem to deliver what they promised (per their specs). never seen drivers run in series.
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Nevermind, I see that you can find single drivers that will work fine.

The theory does indicate that driver should be able to be run in series, but it's not important.
 
This is from meanwells FAQ section..

Can LED power supplies be connected in parallel?

Ans:
  1. MW LED power supply does not have parallel “current sharing” function so it is not suitable for parallel connection. For high power requirement, please select higher wattage power supply or divide LED load into smaller subsections to be powered by individual power supplies. Example of such LED configuration can be found in figure 5. As shown in fig. 5, the connection between -V of the LPC-35 units should be severed and not connected in common. On the contrary, small wattage LED loads can be connected in parallel and be powered by a single high wattage power supply. But, the ability to divide current evenly must be taken into consideration.
 
There is a graph on the Meanwell hlg datasheets that shows you how load affects efficiency.

It is important to remember that dimming to 50% does not cut load to 50%. Even @ 100mA the voltage of a 36v cob is still over 30v so the load is still ~120v combined, which is nowhere near 50% load of the 143v driver.

If you buy the hlg-120h-c1050b driver, and throw 4 cobs on it, you will be at ~136v combined out of 148v max.
[This is the setup I currently run but 4 x 77v cxa3590 on a 120h-c500b]

Edit: aggressive autocorrect fixed
dandyrandy said:
So at what point is the cob efficiency and driver efficiency dimmed become a problem. I'm looking at running 4 3590's at ~ 35w each with a hlg-185-c1400b driver. I think the number is correct. At work now. Will dim to get the 30 to 35 w each I want. The driver at full rated power is 94% efficient. What percentage will I lose in efficiency on the driver? Probably less than the gains on the cobs? The pwm supplies I am used to we use for motor control, standard power supplies, etc. Most are pwm switchers which are more efficient when loaded less. Not sure about these. Duty cycle less in most supplies means more efficiency. Less current less duty cycle on time of the pwm signal which forms the DC.
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