12v dc Cree xre q5 and drivers?

Cree xr-e Q5 Homelighting retrofit.

Hi
I'm a noob who's interested in making up an led light setup that could be solar powered ultimately hence the 12v+ need.
I'm thinking of using these http://www.dealextreme.com/details.dx/sku.2394 probably 3 at a time at 350ma but I'd like the option to use them at 700ma or thereabouts if I need more light. I'm not really interested at running them above as it seems heat is a major issue for not a lot more light output?
I've found these http://www.luxeonstar.com/buckpuck-1000ma-dc-led-driver-pcb-mount-p-8.php and they seem to do evertything I want but at $20+ with postage and import duty the cost will soon mount up.
Does anyone know if these are any good?
I've also come across these http://www.dealextreme.com/details.dx/sku.13557 and http://www.dealextreme.com/details.dx/sku.13555 could I use 3x1 watt in series and still get the 350ma output? As space isnt an issue I thought I could double up on these with a 2 way switch controlling them allowing the 2 light settings I want?
I've also come across this thread https://www.candlepowerforums.com/threads/201392&highlight=buckpuck which looks like a good low cost alternative if there are any equivalent drivers that work at 12 volts?
I've also just found this one http://www.cutter.com.au/proddetail.php?prod=cut793 which looks like a good piece of kit.
I'm in the UK so postage, customs is a bit of an issue and my budget is very limited so any advice would be appreciated I know how to use a soldering iron and have a very basic knowledge of electronics but havent got a clue when it comes to all the calculations etc

Paul.

Ps Sorry for such a long first post!

Before we can really advise you on your picks, tell us how you want to use these leds and where in your home/property.

Your goal being a noob is ease of assembly, ease of availability, and low cost.

We got you covered, we just need to know what, where, and when. OK?

Bob E.

Hey
I bit the bullet last night and ordered a wired dimmable 700ma Buckpuck from luxeon star, 9 Cree Q5's WG and a couple of the cheap fixed current drivers to play with from deal extreme
I'm planning on substituting the low energy light bulbs in my 3 lounge uplighters with them as 2 have recently blown. The existing ones are 9W and rather dim. I'm not really fussed about the colour of the light as I thought I could replace the Leds in the future when warmer tint, more efficient ones become available for a better price.
Initially I was going to run them off a 12v car battery or get my mate to find me a golf buggy battery or 2 I also have some cpu heatsinks lay about and was hoping those could be adapted as heatsinks.
I think my first proper question now is what capacitors would I need to fit to the buckpuck inputs as I will no doubt want the batteries to be more than 18" from the buckpuck?
My house is currently incomplete lol The lighting citcuit is only wired for the 1 room so I was going to try and replce the existing bulbs with leds, its wired in 1.5mm twin and earth thats rated to approx 15 amps IIRC.

Cheers

Paul.

Let's start with the buckpuck, did you get the AC powered one or the DC powered one.......If it was the AC powered one you will need to purchase a cheap transformer (like for doorbells) that converts 120VAC to 16VAC (perferred by me) or 24VAC. A big one like that would handle multiple buckpucks powering multiple LED fixtures.

DC powered, yes the bigger the battery the better (for runtime) but even a small one with a quality trickle charger (think batterytender) and you would again be able to power the crap out alot of lights. And remember, for DC power ONLY use a 220uF, 50V capacitor...I would put it across the input wires that come with the Buckpuck....you will probably shorten them a bit I am sure, just keep everything nice and neat (and covered) and you will be OK.

​

Uplighters....circular piece of alum preferred, and I would try 3 for a start.

Warm LED's are available, and reasonable, just not as bright electron for electron that you throw at them. I have gotten a bunch of warm white Seouls from Mouser....their part # 889-N32282, which is Seoul's p/n N32282. Google the part #'s and you can get the spec sheets and look at the pdf from mouser with all the seoul led's you can get. Recommend you get stars because you have big pads to solder to, and you can just epoxy them to the chunk of metal you have.

Play with the stuff you are getting. Think of this as your research phase. Expect to NOT keep much of anything the same except maybe the BuckPucks. Other than that, you will be experimenting with heatsinks, metal working, glue, and increasing your handy man skills!!

Bob E.

Hi Bob
I bought BuckPuck 700mA DC LED Driver (With Leads) (3023-D-E-700) = $15.99 I'll start looking for some capacitors asap.
For heat sinks I was hoping to use parts of this lot cut down as I have them lay about.

The uplighters are like this (please excuse the state of it lol)


I'm already pretty handy, I mess with electrics, plumbing, metalwork, welding, car engine conversions, pc's etc, jack of all trades, master of none
One thing I did forget to order was the glue what type do you recommend to fix the led's to the sinks?

Paul.

Edit : I've found what you recommend in another post. I can get it here but its expensive for such a small amount! http://cgi.ebay.co.uk/Arctic-Silver...ryZ46322QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
Do you think this would be up to the job? The reviews look ok. http://www.dealextreme.com/details.dx/sku.4579

Just remembered I have a couple of these HID lenses knocking about aswell.

Paul Baldwin said:

Hi
I'm a noob who's interested in making up an led light setup that could be solar powered ultimately hence the 12v+ need.
...
I've also come across these ... http://www.dealextreme.com/details.dx/sku.13555 could I use 3x1 watt in series and still get the 350ma output? As space isnt an issue I thought I could double up on these with a 2 way switch controlling them allowing the 2 light settings I want?

Click to expand...

So you're saying use one of the 3*1W boards to give 350 mA to three LEDs in series and two to give a total 700 mA to the three LEDs?

Hey,
I realised after I'd posted that the ones I've ordered are 3w led's, right? So going by the topic on that page a 3*1W is only going to drive 1 led @ 700ma? The other 3*1W led driving 1 led @350ma? Or wont it work like that? I only ordered a couple as they are so cheap.
I was hoping to run 6 off the buckpuck so that leaves me 3 to play with with the cheap drivers, maybe for the front door at a later date?

Paul.

Paul, you could end up with something really cool here.

May I suggest you place one LED facing down to light just the bottom part.....and maybe have that just light the bottom only (cool mood light) then place 2 or more facing up and have the on/off switch control there.

Those old CPU heatsinks are perfect. I will tell you this though, I used a 1000mA DC powered dim capable Buck Puck on a old P3 or early P4 heatsink (2 inches x 2 inches....I think) and it would get warm to very warm when on for a couple of hours. Stromberg showed pictures of his uplight setup further down on the forum here to aid in cooling so don't throw away those fans yet, you may need them.

I know Artic Alumina Thermal epoxy is pricy but it is worth every penny. Literally, just a little dab will do it. So it will last for a long time and will guy ALOT of leds down.

Bob E.

Hey Bob
I've got some 10mm leds I bought a couple of years agoI could use in the bottom of the lights. They were crap so didnt end up using more than 15, I bought 100 lol
I think I'll buy some chrome paint in a can too, if I can find some good stuff and coat the inside of the light to help things a bit.
Your info about the buckpuck is a pain lol, it says on the blurb that they need no additional heatsinking I thought that might have been too good to be true.
I've seen Strombergs post, the effect looked really good! Dont worry the fans aren't going anywhere!
2 of the sinks are approx 3 1/4"x2 3/4" x 2" deep roughly the same as his, so 3 leds should be better? I'm considering slicing them into 1/3's, gluing and arranging them differently as they are different to his. So I might just need both types of thermal epoxy
Rough arse I know lol I wondered if a chimney effect might be beneficial tho?

Paul.

Re: 12 V DC Cree XR-E Q5 and drivers?

Paul Baldwin said:

Hey,
I realised after I'd posted that the ones I've ordered are 3w led's, right? So going by the topic on that page a 3*1W is only going to drive 1 led @ 700ma? The other 3*1W led driving 1 led @350ma? Or wont it work like that?

Click to expand...

Someone here says those MR16 drivers use the PT4105 chip, so I don't really see what difference the 1*1W and 3*1W drivers would have, since it would regulate at 350 mA however many LEDs were connected (without voltage limits, at least).

As I mentioned a few posts back, the 3*1W would be the one that drives three LEDs in series, each at a nominal 1 W - actually 350 mA (claimed). If you want a constant 700 mA then you may be able to run a couple of those drivers in parallel. A simple two throw, single pole, centre off switch would do the job quite nicely if it turns out they're happy in parallel.

BTW, it's mA not ma, and W not w.

Hey

Paul Baldwin said:

Hi
I'm a noob .... I know how to use a soldering iron and have a very basic knowledge of electronics but havent got a clue when it comes to all the calculations etc

Click to expand...

Sorry but I was a bit confused by your initial post as it appeared you asked me 2 questions (indicated by your question mark at the end of the sentence?) I was going on the info I found here https://www.candlepowerforums.com/threads/188227&highlight=PT4105+12v
"$2.53 ea. Buck regulator based on PT4105 chip, 12-16 V AC in. Will also work with DC (PT4105 can handle 5-18 V DC in) - you wouldn't need the rectifier so you could short that out, but it will still work (slightly less efficiently) with it. Constant current out 320-350 mA for 1 W versions, 650-700 mA for 3W version (not 320-350 mA as stated). There's also a socket available for them." but the info seems to conflict so wasn't quite sure.
Thanks for the heads up on mA and W I'll try to remember in future Please forgive me as I haven't had anything to do with electronics since doing the basics at school nearly 20 years ago.

Paul.

Re: 12 V DC Cree XR-E Q5 and drivers?

Paul Baldwin said:

Sorry but I was a bit confused by your initial post as it appeared you asked me 2 questions (indicated by your question mark at the end of the sentence?)

Click to expand...

Sorry, I should have worded that better. I was wondering if you were thinking of using a 3*1W board to give 350 mA to three LEDs in series, and being able to switch on a second 3*1W board to give an extra 350 mA to the same three LEDs, for a 700 mA total.

You're right, the information does contradict. The "12" of "12 V AC" is its RMS value, which is 0.707 of the peak value, since the AC voltage would (should) vary according to a sinusoidal curve. That means that 12 V AC is about 17 V peak, or perhaps a maximum of 16.7 V DC after being rectified, allowing a bit for voltage drop across the rectifier diodes. So I don't see how DX has rated the things for 16 V AC, which would be 22.6 V peak - that's clearly outside the spec of the PT4105. I've updated that list. I think it makes a bit more sense now.

Re: 12 V DC Cree XR-E Q5 and drivers?

Hey
well when they do arrive I'll take some close up photos and post them up so you can differentiate the differences between the two items.
The buckpuck arrived yesterday, fair play to Luxeonstar.com It came in an obscene amount of packaging for such a small item but atleast its undamaged lol My first screw up is ordering one with leads and no pot I thought it came with one. Will have to source one from elsewhere now.
I still havent ordered any thermal epoxy yet, really must get round to it!

Paul.

Great job. I'm interested in doing the same thing. Keep up the good work and I'll be looking forward to progress you'll be making.:twothumbs

Apparently my leds have arrived I'll go pick them up this evening and have a play with them then hopefully

Well, really chuffed with how bright they are Although the spread of light isn't ideal for these fittings. The sink is currently lying loose in the fitting so I can easily adjust the angles till I decide on the one I want. I think a flat setup like this should be satisfactory but this means I'll have to find some more heatsinks of this design as the others are different theres not enough room on them for 3 leds.

Paul.

After having trouble finding more heatsinks cheap enough and doing it the easy way I decided to carry on a bit more with the initial plan


Before

After

Or


Wish I still had access to a donkey saw and surface grinder lol.
The cut down sinks appear to work very well indeed I think I should be able to quite safely reduce them in size quite considerably?
I've tried messing around with the lense I have but I'm quite happy with the spread of light as it is.

Paul.

Let me get this straight- you cut those heat sinks, in thirds, by HAND?!?!?!?!

(My arm is aching in sympathy)

Lol, afraid so. I think it was worth it tho It would have helped if the blade had been sharper.
One thing I am dissapointed with is there seems to be a fairly large reduction in light output when I connect up 3 more leds in series I thought they were meant to put out 700mA regardless? It looks like I may need to buy a 1000mA one to compensate for it.