Noobie Driver Wiring Question

[Mattaus]

Hi all,

Quick noobie question in regards to correctly wiring a series of LEDs together. I don’t know the first thing about LEDs and their drivers and how they work together so take the following in good humour please:


For the record I did search the forums but it was very hard trying to nail down the right search terms to use that didn't return what seemed like every post ever submitted! I did read a few however, but I still have the same questions.

I have my own assumptions but I want to make sure it’s right before I solder and apply power to things…plus I’m having one of those days where I constantly second guess myself. Very frustrating :shakehead

Example time: 3.4-4V 350-1000mA LED plus a 3–9V 350–700mA Driver.

How would I wire the LED and driver in series with another 3 of each in order to obtain as close to a 12V system as possible?

Is it correct to assume that it’s the drivers that need to be wired in series, with the LEDs then hanging off each driver? Seen as the driver is the one sucking the juice from the battery (and then providing it to the LED) this makes sense to me… the driver is parallel to is own LED, but in series with the next driver. See diagram below to explain my stupidity:



If I hook 4 of the 3V drivers up to a 12V battery all in series (as per the diagram) then the drivers should each consume 3V@350mA, and thus provide each LED with 3.4V@350mA. I’m assuming that’s the job of the driver – to act as a transformer of sorts?

Correct or totally missing some very basic understanding of power principles? I can’t help but feel I’m making a total arse of myself.

Any help would be greatly appreciated, even if it's a nudge to a post or weblink.

- Matt

 

[Lumencraft (Matt)]

Hi Mattaus,

Welcome to CPF :)

Way to at least try to think this out for your self man. You really aren't too far off base. To me it looks like there is one fatal flaw in the system you have pictured there. Most driver boards do not work well in series. There may be a few out there, but its very very uncomon to see them used in series.

Most single mode driver boards can be used in parallel, but thats not going to accomplish your goal.

If you want to run 4 LEDs off a 12V system than it will be far easier to get one driver board that can run all 4 LEDs off 12+V.


For example "IF" your battery voltage really is 12V MAX then you could use a blue shark driver.
http://theledguy.chainreactionweb.com/product_info.php?cPath=48_49_61&products_id=1136

You would wire them like this. From the battery to the driver, then to the LEDs in series.


If you are planning to use this in a car then the voltage coming off your alternator is going to be more like 14.6V and you would have to either add a fifth emitter or use a slightly different driver because for the blue shark voltage in has to be lower than the combined total voltage required by the LED string.

 

[Norm]

Poorman Mutli-LED setup method
Norm

 

[Mattaus]

Ok to try and shed some light (pun intended) on why I'm asking these questions please see here: http://www.candlepowerforums.com/vb/showthread.php?312129-Snowboarding-at-night...&goto=newpost

To save you the time I am trying to build some lights to run off deep cycle batteries so we can snowboard at night here in Australia. Unfortunately all our snow falls in national parks and generators are illegal to use in these areas.

Being on a budget and hands on kind of guy (Avionics engineer by trade) making the lights seemed like a logical step. Electrical stuff was never my forte, but I do learn quickly. 12V is ideal because deep cycle batteries are generally 12V.

I may have to post another thread asking about recommended components (or at least look for a thread on this) because I'm getting lost very quickly with all the different LEDs, Drivers etc. I purchased this one off eBay as a test (to see how bright it is and to dip my toes in before I go crazy), but I'm starting to think it was a waste of time and I don't even have it yet!:

http://cgi.ebay.com.au/ws/eBayISAPI...444370&ssPageName=STRK:MEWNX:IT#ht_3307wt_905

I'm trying to build something like these: http://www.litestorm.com.au/xtreme/ls12x.htm

But really anything that floods brightly will do :twothumbs

I'll keep looking but as it stands I'll just go with that Blueshark driver and any LEDs it specifically mentions lol.

the blue shark voltage in has to be lower than the combined total voltage required by the LED string.

So the voltage the blueshark puts out is higher than it's input voltage? So as long as the LED string is greater than 12V then hooking the blueshark up to a 12V battery won't be an issue? Or am I lost...again.

Poorman Mutli-LED setup method

These confuse me no end right now but I'll research it and see what I can decipher. Thanks!

 

[Lumencraft (Matt)]

Poorman Mutli-LED setup method
Norm

This is normally a very good choice for driving multiple LEDs, but in this case I dont think its applicable because 12V is less than the needed voltage for the 4 leds and a 7135 driver will not boost current.

I may have to post another thread asking about recommended components (or at least look for a thread on this) because I'm getting lost very quickly with all the different LEDs, Drivers etc. I purchased this one off eBay as a test (to see how bright it is and to dip my toes in before I go crazy), but I'm starting to think it was a waste of time and I don't even have it yet!:

You are keeping up just fine your not too far off base with your plan at all. Just think of it this way, every question you ask here is saving you money.

That little bundle from ebay is probly not going to get you where you want to be. There are far better sources for the components you will need which myself and others will point out along the way. Since you are in AU Cutter electronics is one of the first to come to mind. If you dont know what you are looking for the website may be a little challenging but we are here to help so dont fret.

I'm trying to build something like these: http://www.litestorm.com.au/xtreme/ls12x.htm

But really anything that floods brightly will do :twothumbs

I'll keep looking but as it stands I'll just go with that Blueshark driver and any LEDs it specifically mentions lol.


So the voltage the blueshark puts out is higher than it's input voltage? So as long as the LED string is greater than 12V then hooking the blueshark up to a 12V battery won't be an issue? Or am I lost...again.

Yes that is basically correct. The blue shark is a "boost" circuit. There are some limitations to how many LEDs this can drive though.


I know this is a lot to absorb and I dont want to confuse you any further, but now that I know exactly what your doing, I thought of another option for this that may be an easier build and would put out more light per unit.


Rather than using the blue shark (which are a bit delicate IMO) you could use a bit more robust driver like the H6CC.

This driver would allow you to run more LEDs on a single board or run your existing 4 at a much higher current. The only real difference in the way you would wire the leds.

http://www.taskled.com/h6cc.html


Here is what I would do and why.




This may look complicated but I will try to explain so you understand.

The LEDs I would use are Cree XML T6 on a 20 MM star, these will be very bright, floody and easy to use.

This is a 3 series 2 parallel connection. You could set the output of the driver to 2 amp. Since you have 2 leds in parallel the current divides between them for 1A per die. The reason I say to do 3 series is so that the voltage requirement for the LEDs to run is about 8.4V. The H6cc requires at least 1V above what the LEDs need for power. That means your battery can never be discharged below 9.4V. This should help to protect your 50-100$ battery investment.

Just be sure that with all that LED power you have a good heat sink for them.

 

[Mattaus]

Instant-email notification my a**.

Wow...nice post. Thanks so much!

I'll probably go with the suggested design you drew up however I have a few questions regarding the LEDs. The driver seems very straight forward but as usual these LEDs are giving me the willies.

What's the difference between this cutter branded T6 (http://www.cutter.com.au/proddetail.php?prod=cut1027) and this drop in unit from Deal extreme (http://www.dealextreme.com/p/cree-xml-t6-1-mode-6700k-450-lumen-smooth-aluminum-drop-in-module-55025) other than the fact the DX one has a driver and reflector included? That DX Lumen rating seems BS.

Is that cutter LED just a rebrand or is XML T6 a universal thing and not a Cree specific thingy? (see...clueless!)

The HC66 is $32, and 6 of the cutter LEDs are approx. $60. Thats close to $100 and it's almost be pointless making my own when I could buy something similar for a few dollars more (I'm exaggerating a little but I'm sure you understand) Although I guess there is always the chance that your solution is much brighter OR could it be run with 4 LEDs instead?

I see Cutter are the Aussie distributer for TaskLED drivers but a search on Cutter's website turns up nothing for HC66. I'll look harder I think.

Price v performance rears it's ugly head again!

EDIT: looked harder and found the TaskLED section on Cutter. No H6CC but there is a HipCC driver. Same thing? (probably not - it's over $50 so surely it's not). I guess there is nothing stopping me from ordering directly from TaskLED? With the Aussie dollar so strong there is no harm (other than shipping no doubt).

 

[Lumencraft (Matt)]

Ok wow, I didnt realize that cost was going to play such a critical role in this project. To answer your question about the DX dropin and the LED. XM-L is a Cree product. Some companies put the cree emitters on their own brand of board, but the emitter is the same. That DX dropin would not work for your project unless you changed the driver board that comes in it ( its a 4.2V max input).

You could use the setup I pictured with only 4 leds but that would eliminate your low voltage protection.

If you are wanting to do this like dirt cheap and having low voltage protection for the battery is not an issue I do have one other suggestion.

This brings us nearly full circle back to your original idea. You could use a driver like this
http://www.dealextreme.com/p/mr16-1...urrent-regulated-led-driver-8-40v-input-13557

And just run one driver to each LED.




Then just get some cheap plastic optics and figure out something for a casing.

If you wanted to increase the amount of current to your LEDs at any point you could just add another one of those cheap drivers in parallel to each LED.

I'm pretty sure you could use an optic like this one for 2$ I havent used this one with XML yet but they worked great for the older XREs and the single XRE optics I have used with XML have done fine.
http://www.dealextreme.com/p/50mm-4-led-reflector-for-cree-emitters-glass-like-plastic-1915

Again sorry I know it seems like we are going in circles a bit.

 

[Mattaus]

lol don't apologize. You've been more helpful than most that's for sure! I should point out I'm not some tight arse or poor uni student. I just happen to have recently bought my first house, and have many other little projects going on at the same time. Splitting my average pay amongst them all is proving more of a challenge than building this flood light! My own fault, but it's a problem none the less.

To be honest around $100 is OK, but seen as I'm aiming to build 4 complete units, plus the $200 80Ah deep cycle battery, the total cost will be approaching $600 for something I won't use very much...maybe I'll have to go camping more often! Easy to do round these parts.

Low voltage protection shouldn't be an issue as the battery I'm looking at buying comes with a low voltage indicator, though this is only useful if you're looking at it :duh2:

Obviously the max current available to each LED with that DX driver is 750mA so would those Cree XML T6 LEDs still be your suggested LEDs? Or would you recommend something else? Just to clarify, the Cutter LEDs I linked to ARE the CREE XML T6's (never directly confirmed that I don't think)?

So assuming I'm running 4 of the Cree XML T6 LED's off 4 of the cheap drivers in parallel off a 12V battery, the light should theoretically produce approx 1120 Lumens of light with [email protected] (the T6 is rated for 280 Lumens at 700mA according to the spec sheet). Not too shabby unless my maths is rooted. hopefully that's bright enough.

Any Cree XML T6 equivalent LEDs from other manufacturers I should look at? Just so I have some options...looking at DX and Cutter now.

 

[Brian10962001]

Heatsink them decently and drive them at at LEAST 1 amp. 1400ma would be better for long life versus heat, etc. The XML's are very impressive when driven hard, not so much when driven very easy. The XML is a good choice here too because it's floodier than all the other LED's I've messed with in flashlights. Good luck with your build ")

 

[videoman]

Another suggestion if cost is a consideration and you wish the most amount of light.
recipe:

12 Cree XM-L T6 on 20mm stars

6 drivers ( but buy at least 18 of them, I will explain later) from DX (deal Extreme) part # 26110
http://www.dealextreme.com/p/18v-5w-cree-circuit-board-for-flashlights-16-8mm-5-5mm-26110

12 Ledil reflectors Boom ones ( the widest beam angle ones) http://www.ledil.fi/datasheets/DataSheet_Boom-MC.pdf
these should be easy to obtain try Cutter or DigiKey .Iknow,I know, these are designed for the MC-E's but work well on XM-L's

2 kits Arctic Alumna ceramique adhesive

1 nice aluminum heatsink , around 12" X 6" X 2 " with fins to dissipitate heat

1 front Lexan or clear acrylic sheet (easy to cut)

1 rear metal plate ( to cover everything up ) bendable thin aluminum works best

A little pit of patience ( this is the hard part )


Ok so you have 6 drivers to wire them in parallel so each gets the 12V juice from the Batt
Each driver delivers 1200 ma out
Each driver is connected to 2 XM-L's ( the 2 leds are in SERIES ) to each driver.
Space the leds around the heatsink at least 1" from each other
Glue the Ledil reflectors on each star ( Arctic alumna) after the leds are soldered and tested to light (you may have to grind/sand off the feet)
use as little solder as possible ( no huge blobs) 18 single copper strand wire is fine

Everything should cost around $250
You can use half the leds and save around $100 on everything.
Don't forget the on-off switch, high temp silicone or high temp automotive gasket maker (so no snow gets in)

Each led now is driven at 1200 ma ( nice) and be around 400 lumens or more for a total of 5000 lumens
with the reflectors in place the brightness is almost doubled to around 9,000 lux ( beam angle reduced to around 50 degrees horiz/vertical

each led draws around 4 watts or less, drivers are around 80% efficient, battery will last a very long time,
the whole unit will operate from 9 to 18V Dc easily

The drivers are NOT reverse polarity protected, so if you wire them wrong, POOF they go. That's why the extra ones.Make sure you wire them right. If you do, then the extra drivers can be used for your next/additional light you may need.

Good luck !!

 

[Lumencraft (Matt)]

.

Obviously the max current available to each LED with that DX driver is 750mA so would those Cree XML T6 LEDs still be your suggested LEDs? Or would you recommend something else? Just to clarify, the Cutter LEDs I linked to ARE the CREE XML T6's (never directly confirmed that I don't think)? [/qutoe]

Yes the cutter LEDs are cree XML T6

So assuming I'm running 4 of the Cree XML T6 LED's off 4 of the cheap drivers in parallel off a 12V battery, the light should theoretically produce approx 1120 Lumens of light with [email protected] (the T6 is rated for 280 Lumens at 700mA according to the spec sheet). Not too shabby unless my maths is rooted. hopefully that's bright enough.

Yes that sounds about right. Plus as I mentioned before if you decide you want more output you can double up on the drivers and get almost 2x the output.

Any Cree XML T6 equivalent LEDs from other manufacturers I should look at? Just so I have some options...looking at DX and Cutter now.

Not really. You could go to a Cree XPG and save about 2-3$ per LED, but the XML is the most light for the money bar none.

 

[videoman]

I dunno about that ! I received 50 of the DX drivers and am running 2 XP-G's in series with a healthy 1.22 amps going through each led. Mighty bright. Also to note that the newer versions (the ones I got) have the S34 Schottky diode instead of the pictured S24. Anyway 2 XM-L's in series off of this will surely feed 1200 ma. Or did I miss something. ?

 

[videoman]

Driver I have in mind is the DX # 26110 @ $1.99 each

 

[Mattaus]

Wanna include some diagrams and a detailed build guide with that post videoman?* :wow:

I've learnt so much in this thread it's not funny. Best set of questions I've ever asked it seems. Places to look, some basic LED facts and a good idea about what works and what will blow up in my face.

I'm going to have to take a few days (oh would you look at that it's Friday...) to digest this information and try and pick/design a solution that fits my situation best.

If it all works out I'll try and put a build thread up so you can all marvel at your own ingenuity haha.


*I am joking!

 

[videoman]

You will first need something like this : http://cgi.ebay.com/Aluminum-Heat-S...aultDomain_0&hash=item43a5845460#ht_500wt_922
Cut it down so that it is like 10 or 12" long
Wire the drivers (6) and the leds (12) on the flat side. Cement them with the Arctic Alumna adhesive. The underside of each driver has a center copper circle ( that's the +) and the larger ring around it ( the - part)
Use red wire for the + and black for the - . make sure that you do NOT let the + and - underside of the drivers contact the aluminum heatsink or else you will have a short. The Arctic Alumna is going to be the insulator but put just enough so that there is no contact ( like 2mm thick). This stuff dries very fast, like a couple of minutes. You may need 3 kits of AA to do it right. The Leds on stars use much less of the adhesive, the less the better, press down firmly on them. Make sure the neg. and pos. solder terminals of each led pair face each other as they will be connected in series. I would put 6 columns, each column would have a driver at the bottom and 2 leds directly above it. space out the leds/drivers apart. Solder wires and glue down reflectors on them. Before putting the reflectors, light it up and see if the brightness is enough. I would wire up 1 column at a time and applying voltage to that to check for any shorts/ problems before proceeding to the other columns. Leave about 3/4 inch from each side of the heatsink free as that will be the place where the frame for the front clear acrylic will go. The frame can be made from hollow square aluminum of 3/4 inch. cut to size to make frame and glue it down around the heatsink. The acrylic panel can be held over the frame with clear silicone in case of removal. wiring to battery can pass through the back between fins with strain relief and an inline switch can be used . Do the drilling before any electronics work. Don't forget also for drilling holes for tripod bracket support on the bottom edge of frame. I will make wiring diagram and post link to it. Really easy .

 

[Mattaus]

EDIT:

Any reason why I couldn't run the XM-L's with the 14mm base instead of the 20mm star? I understand it's for ease of use and more contact space for cooling, but a 14mm base fit's so much better in the housing i'm looking at than the 20mm star.

 

[Lumencraft (Matt)]

You could use 14mm. I said the 20 because basically all reflectors and optics will fit perfectly on a 20mm board, where as some dont fit as well on smaller. The extra 6mm on that star is not going to make much difference for heat sinking. Again just be sure to stick those stars to a good chunk of aluminum bar or something with a very thin layer of Arctic Silver 2 part epoxy or similar.

 

[Mattaus]

No worries - the heat sink I'm using seems like a good size, but with the housing I'm making it becomes a bit of a tight fit. Then again it will also be practically bomb proof lol.

 

[videoman]

If you are not using optics or reflectors, then you can use the 14mm boards without any problems. The reason for the 20mm stars is that the reflector/optic will have plenty of room to "sit" flat on the board without any solder blob underneath it. Also the fact that 20mm stars are usually more available. A bare led outputs a super wide beam ( over 100 degrees ) in every direction but the brightness will be more with optics/reflectors on them. Just depends on how bright you need it.

 

[Mattaus]

OK here's my deal.

In my housing, from the face of the heatsink to the inside of the plexi-glass cover is 17mm. Those Boom-MC reflectors are approx. 13mm high. Not sure if there will be enough room for the LED and a relfector on top of it or not. This is assuming the cover is 3mm thick.

The space inside the housing will fit either 3x 20mm star PCB LED's, or 4x 14mm PCB LED's. 4 will obviously provide more light.

Now in regards to using the reflectors or not I have a few considerations to make.

No reflectors gives more flood but less intense light. Seen as we wan't to flood a general area maybe I can build 1 light without reflectors and 1 with. One light can flood the whole area, while the other can be focused a little more directly at whatever we are jumping off/slinging from/hitting.

However Cutter seem to not stock the Boom-MC with the widest flood, and even then for some reason their shipping is almost double the cost of the reflectors. This may not be an issue if I bundle the LED's in with them but still...that and if I go with my idea above then the widest reflector may not be idela anyway.

Are there any cheaper/equal alternatives from site like DX etc? Will there even be enough room for them in my housing? 17mm - 13mm give 4mm for the LED + PCB...