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#1
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![]() Wow, you did a really nice job putting that diagram together.
I was hoping to do the parallel thing but avoid the resistors and fuses as I start to feel like it's getting past me in my electrical knowledge. Hadn't thought of doing a terminal block but it's a really good idea.
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Mark... ![]() 290g Peninsula Display, 425g total volume. Setup Jan 2013. |
#2
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![]() the resistors and fuses are simple once you know why you are putting them in and undersatnd whats happening on a parallel string.
ill try to explain it. most of the simple designs you see are one driver per 12 LEDs These are usually powered by something like the meanwell LPC-35-700 This driver puts out up to 48V and .700amps the LEDs are rated to have about 3.5 volts each and .700 amps per series. 12LEDS * 3.5ea = 42V. The driver above will adjust itself down to 42v so the above driver can only handle one series (.700amps) and 12 LEDs (48v). Now lets say you got a big bad driver that does 2.1amps and 48V So now you can only still have series of 12 LEDs (48v). But since you have 2.1amps you need to balance that out between 3 series of 12 LEDs which gives you .700 amps per series. The reason you start needing resistors and fuses is to be "safe" So, if for watever reason one of those 3 series decides to stop, and other two keep running, you are dividing 2.1amps between 2 series instead of 1! Thats 1.050amps per series. If the LEDs cant handle it, boom goes the LEDs. This is why you put a 1amp fuse in before each series. As soon as one series goes, the 1amp fuse blows and your LEDs are safe. So what is the resistor for? Well for you to measure the amperage on each series you need to un-solder and put a multimeter inline with the leds. Well of course this sucks. If you put a 1ohm resistor at the beginning of each LED series then you just measure across the resistor while its inline and it will tell you the amperage. From my understanding the amperage can vary per series so you want to switch LEDs out and get them as close as you can to each other. Over time it can change also, so having the resistors in there for quick tests works great. |
#3
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![]() Thanks for the quick explanation. I will end up putting in both the resistors and the fuses now that I know where to get them and why. You should make sure you take some detailed pictures of your wiring to the terminal blocks, how the jumpers are setup and your wiring of the fuses...(so that I can copy of course
![]() Any luck with the info from ETG on Neutrals and Blues?
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Mark... ![]() 290g Peninsula Display, 425g total volume. Setup Jan 2013. |
#4
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![]() why did you decide to run them at 0.7amp instead of 1 amp? just curious.
Steve
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![]() Some strive to be perfect.... I just strive. |
#5
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![]() running the LEDs lower than max Amp (so 70%) makes them last longer..
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#6
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![]() Although I agree wtih you about the lower ma rating generating less heat and therefore extending the life of the LED, I am hoping to find a way to push the XP-G's up to 1000ma as their max is 1500 and 1000 should still leave a very long life.
I know you have found all the other items you need...but have you ordered them already?
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Mark... ![]() 290g Peninsula Display, 425g total volume. Setup Jan 2013. |
#7
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![]() Quote:
XP-E royal blue are 1000. I might switch up my design to handle 1000 for the cool white. |
#8
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![]() Quote:
I would personaly go with 1000mA for both as you are also using fuses and resistors to safe guard and dimable ballasts so the chances of you ever comming close to a situation where you would pump enough current/voltage to dammage the LEDs are going to be very very slim to none. most people just run 1000mA dimable meanwells and nothing else and are not having problems. but I do like the idea of the fuses. not sure I like the parallel idea but I guess with the resistors you put to rest any concerns I have there. Steve
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![]() Some strive to be perfect.... I just strive. |
#9
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![]() The problem with a large build and not running parallel is that you would need a massive amount of the ELN-60-48 meanwells and they are not power factor corrected. As such, the In-rush current when/if you turned them all on at once has been considered dangerous for overheating the wiring at the receptacle.
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Mark... ![]() 290g Peninsula Display, 425g total volume. Setup Jan 2013. |
#10
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![]() <deleted post - may have contained inaccurate information - sorry!>
Last edited by abcha0s; 01-19-2011 at 06:29 PM. |