Building New Panels - Sharing the Process

[cimenk_hel]

Is it possible that an XM-L bin T2 has higher lumen output and higher efficiency than bin T6? Or is the site I'm looking at making a systematic mistake in their notation?

 

[rrog]

?? I thought the bin directly meant higher output? I copied this from some page or post:

the Bin code indicates the efficiency of the light for the LED. *The top code is U3 and the lowest code is the T3. *For instance, a U3 Cool White will output up to 60-80 more lm at 700mA than a T5 Cool White.

 

[cimenk_hel]

I thought so too. It took me a while in the first place to get all the talk of bins and such; now, coming across what I mentioned, I started to think I got it backwards, or that there's more to it... If you want to check it out, I can give the site or direct link, just ask... I just found it again.
The only difference I can tell (besides the T2 bin one generates more light, and more lumen/watt than the T6), is that they have different manufacturer codes: the more efficient T2 is "XMLAWT-" and a string of zeroes etc, the T6 is "XMLEZW-" and a similar string. The T6 has also a higher rated max current.
I though all XM-L are maximum current 3000mA and thus all having very close to 10W max power output?
rrog, I'd pm you the direct links to these items but I can't. Should I post them here? If I can't get an explanation for this, I can't really trust the site I'm talking about...

 

[rrog]

I just searched for the highest Bin I could find for the LEDs I wanted. Now I'm simply planning the series wiring routes.

 

[luvdemshrooms]

XMLAWT's and XMLEZW's are physically the same, yet perform differently.

You aren't quite comparing apples to oranges, but instead are comparing 1 variety of orange to another.

While you'd think the bin codes SHOULD remain comparable from one LED to another... they do not.

 

[rrog]

I can see laying out this little box with all the MOVs, drivers, fuses, etc is going to be a treat. Is there any required order for these? Fuse - MOV - Zenner? MOV - Fuse - Zener?

All on the AC side

 

[cimenk_hel]

@luvdemshrooms. I understand there are small differences, this is kind of implied in the very existence of this binning system. BUT, the differences I cited are quite big? like 20% in power, almost 50% in lumens/watt.

 

[luvdemshrooms]

Again, they are two different creatures.

All XML's are not created equal.

Were I in charge at Cree, a T2 would always be a T2. Alas, I am not in charge nor did they ask for my opinion on their binning methods.

 

[cimenk_hel]

Are you saying they use different criteria for binning than just wattage, lumens at a certain current, and other things we look at? This gets confusing. Might be wise to just order whatever bins come along, but with specs as close to each other as possible? For leds on same strings at least.

 

[rives]

I can see laying out this little box with all the MOVs, drivers, fuses, etc is going to be a treat. Is there any required order for these? Fuse - MOV - Zenner? MOV - Fuse - Zener?

All on the AC side

The fuse should go first, just like the circuit breakers in your house. The MOV's would then go across the power (L1 & Neutral) as close to the fuse as possible to try and quench the spike before it gets downstream.

The zeners go on the DC side, not the AC. If your driver box is going to be remote from the LEDs, I would place the zeners in the LED side so that they have static protection when disconnected from the driver box. In order to protect both power rails from overvoltage, you will want (2) zeners, hooked back-to-back (in series). Lay the diodes out so that the ends with the stripes are facing away from each other, and solder the leads from the plain ends together. This assembly is then placed between the (+) & (-) leads from the driver going to the LEDs.This arrangement keeps them "open" until their voltage rating is exceeded, and at which point they will turn on and short from one power rung to the other.

 

[rrog]

Thanks for the clarification, Rives. I want the protection you've detailed. The driver box would be connected to the LEDs all the time, unless I'm re-building the board, I imagine. The remote Zeners on the DC side would help in that eventuality. I will try and look up this connection strategy you described. Not having familiarity with any of this makes it hard for me to understand what any of that means, so I hope to just buy all the stuff and hopefully it'll make sense when in front of me.

So would there be a fuse block and a MOV block right next to it? I'm just ordering a bunch of those Radio Shack blocks you provided a link for. That's pretty close to making sense to me. The Zener deal isn't as clear but I'll work on it.

Thanks for all the help and encouragement. This is still daunting to me.

 

[luvdemshrooms]

Are you saying they use different criteria for binning than just wattage, lumens at a certain current, and other things we look at? This gets confusing. Might be wise to just order whatever bins come along, but with specs as close to each other as possible? For leds on same strings at least.

Not at all. I'm saying that rather than focusing on what they call a bin, focus on the specs while being sure that it's for the same LED. While doing so remember that there's also a XMLHVW which runs at 46v rather than the usual 3ish volts.

If you want a LED that generates 140lpw, look for that. Don't worry about what they call the bin, Focus on what the bin will do, rather than what they call it.

If a XMLEZW was the same as an XMLAWT, they'd call it an XMLAWT.

 

[rives]

I will try and look up this connection strategy you described. Not having familiarity with any of this makes it hard for me to understand what any of that means, so I hope to just buy all the stuff and hopefully it'll make sense when in front of me.

So would there be a fuse block and a MOV block right next to it? I'm just ordering a bunch of those Radio Shack blocks you provided a link for. That's pretty close to making sense to me. The Zener deal isn't as clear but I'll work on it.

Thanks for all the help and encouragement. This is still daunting to me.

It won't make much sense until you get the parts in front of you. The zeners, like any diode packaged that way, have a stripe on one end which indicates polarity. It is critical for their proper operation that they get oriented properly. They will get hooked up like this, with a solder connection where the "X" is. ----[I___]---x---[___I]----

*edit* The damn automatic formatting keeps removing the extra spaces in the representation of the diode above, so it isn't as clear as I would like. I replaced them with underscores to keep the spacing. Look at the diodes, it will be pretty obvious what I'm trying to show.

Depending on the type of fuse holder you wind up using, the incoming power hot lead will go into one terminal on the block, and the other side of that terminal will feed the fuse. The other side of the fuse then comes back to the terminal block and will feed one side of an MOV as well as feed the power to the driver (paralleled). The remaining lead on the MOV will go to the neutral, as will the neutral wire from the driver.

If you want a power switch on the driver box, connect the black wire from your power cord to one terminal on the switch, and then come from the other side of the switch to the first terminal above.

Once you get the parts in hand, if it doesn't clear up for you let me know and I will draw up a diagram.

 

[rrog]

I'll get everything ordered up and have a look. I had hoped that the local Shack would have had all this so I could see it then and there, ask the guy, etc. 'Twas not to be...

EDIT: The Fuse Holder: http://www.radioshack.com/product/index.jsp?productId=2062258

The Terminal blocks I'm ordering for all these items. As I understand it, all the Zenners, and MOVs will fit in these: http://www.radioshack.com/product/i...terName=Cable+type&filterValue=Terminal+strip

I'm ordering 6 just in case...

 

[rives]

With that style of connector on the fuse holder, you can either use 1/4" quick-slide crimp terminals to wire it, or solder the wire directly to the tab.

The terminal blocks can easily be cut to length with a hack saw or razor saw if there are way more terminals than you will need, or your space is limited.

 

[rrog]

Hitting RadioShack.com for the terminal blocks and Mouser for the MOV's http://www.mouser.com/Search/Produc...0BPvirtualkey57610000virtualkey576-V150LA20BP

and the 45V Zeners

I have 5 drivers, so 1 Zener and 1 MOV per driver, yes?

EDIT: I'm not finding Zeners at 45V like you suggested unless they look like this:

Radio Shack is out of those terminal blocks online... Go figure. I'll look on Mouser

 

[luvdemshrooms]

----[I___]---x---[___I]----

What are you trying to accomplish with two Zeners oriented like that?

 

[rives]

You need to find a zener that is comfortably above the maximum voltage that you are using. You may need to go up to 46 or 47 volts, the voltage increments get wider at higher voltages. That is an unusual looking package for that zener, but I'm sure it would work fine. I'm used to seeing the package style shown in the attached DigiKey link. You want (2) zeners per driver, but get spares. They are cheap and will very possibly blow up when they do their job.

http://www.digikey.com/product-detail/en/1N4756A-TR/1N4756AVSTR-ND/3104083

LDM, zeners oriented in that fashion will turn on with a spike on either power rail.

 

[rrog]

I'd order everything from DigiKey but a quick search for Terminal Block there pulled up a few thousand results. Amazing depth of inventory at these places... Wow.

 

[luvdemshrooms]

That is an unusual looking package for that zener, but I'm sure it would work fine.

That's a rough representation of a standard surface mount zener.


http://www.digikey.com/product-detail/en/1SMA5913BT3G/1SMA5913BT3GOSCT-ND/917671

LDM, zeners oriented in that fashion will turn on with a spike on either power rail.

Are you trying to make a TVS by doing that? I ask because after many years of doing electronics work I've not seen two Zeners installed in opposing orientations.