12v dc Cree xre q5 and drivers?

[SafetyBob]

Paul, outstanding work there!!!!

I believe if you are hooking up 3 more LED's to the 3 you already have, that is your problem. With 6 * 3+VDC Vf, you would need to use around 18 to more like 21VDC to make them all bright again. You could try to parallel the 3 with 3 more, but that my be to much for the tiny BuckPuck to handle......possibly.

Now I must go figure out when I have time to get this project into my schedule here.....not that I don't already have about 1,800 infront of it already!!

Bob E.

 

[Paul Baldwin]

Hi Bob,
I'm running 2 strings of 3 leds from the Buckpuck already as it says you can in the pdf on the website I bought them from. I borrowed a friends volt meter last night as mine still hasnt been returned to me lol. The car battery I'm using was only reading 10.2 volts. I'll have to see what difference is made when I get hold of a charger to put some more juice back into it, I think that may well be affecting the performance.
As I only bought 1 buckpuck I thought I'd use 2 leds for now in the 3rd light using the other cheap m16 drivers. The combination of 1 1x3W@700mA and the other 3x1W@350mA is actually brighter than 3x700mA leds run from the buckpuck at 10.2 volts. While playing with the 1x3W driver when I first got the leds we found it still worked even down at 7 volts, so they really are quite flexible I thought I'd risk the 3x1W driver on a 3W led and it's suffered no ill effects after 5 hrs last night.
The M16 drivers only have a slight difference to each other? One has two resistors installed, the other has one and the 3x1W has a smaller capacitor. I was wondering if I could make them dimmable as they are a much cheaper alternative to the buckpuck?
The only real advantage the buckpuck has at the moment is its not getting hot at all whereas the M16 coils get hot and they have a lower efficiency from the info on the dealextreme website.
So what are you working on at the mo?

Paul.

 

[Paul Baldwin]

Another udate. I've borrowed a 12v car battery charger. Initially without the charger connected the leds were quite bright again, I took this as being caused by the battery recovering to a higher voltage since the lights were switched off. After 10 mins they were noticeably dimmer off the buckpuck than the cheap drivers. I connected the charger then with the leds on and they immediately became brighter
I then disconnected 1 string from the bp and still the others get brighter but brighter than the 2x leds in the 3rd lamp even! more as I'd expect them to be anyway.
I'm wondering if I'd get more light or on a par from 2x2 strings on the bp instead of 3x3 at the voltage I'm using? This may also allow me to have more flexibility with the battery before the leds start to dim?

 

[Ken_McE]

I quite admire the blast of light you're getting from each fixture. If you want to change the color tint you can add in a few of those cheap little LEDs next to the big ones. I'd suggest yellow or perhaps red to even up the bluish quality of the light (if you care to fiddle with it) When you do the final install of the heatsinks I'd sugest raising them up off the floor of the fixture just a touch to let air get under them more easily.

Let me get this straight- you cut those heat sinks, in thirds, by HAND?!?!?!?! (My arm is aching in sympathy)

The man is clearly a throwback to the glory days of Britain when iron men rode forth in wooden ships.

PS, what's "chuffed"?

 

[Paul Baldwin]

Hey, "chuffed" is just another term meaning happy with the result As for the iron man bit lmao, if you saw me you wouldn't think that, I'm a skinny, lanky, streak of ****! TBH it would have been easier if the blade was sharper, I used the lubricant in the photo to stop the aluminium from clogging the blade. If you spray the blade when its half in and half out the job it has no choice but to drip into the slot and makes life easier.
I have a standard lamp in another corner of the room with a 4W flourescent fitting in that gives off a pleasant yellow light, this "fills in" quite nicely and makes the led light less harsh. I plan to replace these leds with warmer tint ones when the technology has caught up and the price has come down
The last photo isn't quite a true rendition of the output, I adjusted the ISO to 200 for that shot, don't know why now thinking about it lol, maybe I should replace that photo with one at 100ISO as it is a truer representation of the light output.
I think an airgap under the heatsinks with the 3 leds mounted that are effectively upside down would probably be a good idea. The other sinks that require the extra work to make (typically lol) appear to work very well indeed though, they barely get warm at all even after being on for 5 hours. I'm pretty confident that even if the ambient temperature in the room was 35 degs C that they would still keep cool enough! Something tells me that isn't going to be a problem though, our weather for one and the fact one wall is made of stone and is 20" thick being another. It's more like living in a fridge than a cottage sometimes

Paul.

 

[Paul Baldwin]

OK, I've got my meter back. I've taken a few sets of readings at differing voltages with the battery connected and disconnected from the charger. It seems that the cheap 3x1W and 1x3W driver are drawing a lot more current as a percentage of the total compared to the 6xleds driven by the bp.
1.With the battery pretty much topped up and the charger connected I got. 13.27v under load. 2xleds=0.34A, 6xleds=0.52A, 8xleds=0.87A total.
2. Battery under load after a few hours running leds disconnected from charger 12.06v. 2xleds=0.38A, 6xleds=0.57A, 8leds=0.97A total.
I'm thinking I really need to connect 2x2 strings of leds to the bp and see what it draws. I know its more efficient than the other drivers but the current it's drawing is surely too low? Maybe it's to do with the cable run lengths and the distance the second string is from the bp aswell as the low voltage? Also 2x2 strings should allow the voltage to drop further without the leds dimming as much?
Any ideas what's going on here Bob or Torchboy?

Paul.

 

[Paul Baldwin]

Right, I'm confused lol. I re-measured the bp again. When driving 2x3 strings of leds it was drawing 0.58A. When I disconnect a light and measure again I get 1x3 string =0.61A. No wonder the one on its own appears to get brighter! My understanding on these things was they would provide twice as much current when the load doubled, not slightly less?
I'm also wondering if my multi-meter is subject to doubt. After googling how to measure current to be sure I'm doing it right I've read that the meter should have as low a resistance as possible. My leads are currently reading 0.5 ohms, would this significantly effect the current readings?
Apart from that I'm pleased with the outcome I had some friends round the other night after being kicked out the pub at closing time and turned the single light off and dimmed the 2 others as it was deemed too bright for that time of night!!!

Paul.

 

[SafetyBob]

Paul, if you are running the 1x3W set up from the one Buckpuck and 12VDC battery, that sounds like it should be nicely powered and bright just like you are reporting.

When you add the other string, are you lighting that other one that is close to 2 meters or so away? If so, that is the problem, line loss would be significant and unless you need the brightness (since buddies think it's to bright now), don't worry about it.

If you want max efficiency and such, get two buckpucks, one for each fixture (again, I would suggest the one with the dimmer cable) and you should get max brightness when needed and be able to dim as necessary for pleasing pub mates.

Cheers...

Bob E.

P.S.-I sure could use a nice pint of bitters right now.

 

[Paul Baldwin]

Hey Bob,
I thought that might have something to do with it. It's illegal in the UK to wire horizontally from light to light so the cable linking the two lights is more like 3.5m in length and yes the bp is lighting both of them! You wouldn't believe how far the battery is from the bp. I thought I'd just try it and see if it handled it. After an initial connection and no nasty noises or smells were emitted I thought I'd keep an eye on it and what do you know, it works
I think I'll leave it as it is for now, the current being drawn is acceptable to me and I've another couple of stages I want to try with this project yet and the funds or lack of them, will be better spent there? As you say, if it's bright enough now why mess with it! I like the fact that theres only 1 dimmer too, I'm going to either extend the pots knob or get another one and drill carefully thru the fitting to permanently mount it.
As for the bitter, want some sent over? lol It just so happens that my local Brewery (Hobsons) has won the award for best beer in Britain this year!!!! To be accurate it's the Mild that won and it's a cracking brew and not too strong. They've got a bottling plant too! lol

Paul.

 

[Tekstyle]

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

nice LED set up. and definitely very nice s2000 projectors :twothumbs

 

[Paul Baldwin]

Thanks I think the HID's come out of some sort of Renault lorry over here? They are extremely bright, especially if you have 4 of them on your car lol. I've found that the better quality 62mm DX lenses fit them too, I'm sure they definately would be projectors then!

Paul.

 

[Paul Baldwin]

I thought it was time for an update! I had noticed recently that my retrofitted lights weren't performing quite how I remembered them and it turned out to be a nice simple fix When I initially installed them I was mindfull to run a hoover brush over them from time to time, how long did that habit last? lol.
Clean exposed led domes periodically is my tip of the day. Other than that alls good, personally I don't mind the cold colour of the light from them and my visitors don't seem to either.

 

[Paul Baldwin]

Well, 4 years on and they are still doing the job. Those buckpucks aren't the cheapest option but appear to last! :-D

 

[Paul Baldwin]

6 and a half ish years on and still good. Looks like it was a worthwhile project after all. Sure I will swap a few of the emitters out for some nice high cri ones one day?

 

[gktii]

Re: Cree xr-e Q5 Homelighting retrofit.

This is a great thread! Thanks for sharing your experiments with us. 👍


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[Paul Baldwin]

Re: Cree xr-e Q5 Homelighting retrofit.

Thanks First comment since Dec 2008, glad one person has appreciated it at least lol.