new P7 driver 3amps?

herulach

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Do the new diodes require heatsinking? Does it just move the heating problem elsewhere?
I received my KD P7 driver a couple of weeks ago. It's the newer 17mm version.
Like others here it overheats and cuts out to low mode after 3 minutes running on high. Power is 2x 18650 Li-Ion.

The diodes where getting way to hot, so tonight I changed them.
I used 2x 1N5822 40V 3A Schottky Diodes in parallel.

In Australia you can get them from DSE or Jaycar.

These axial lead diodes are physically much larger then the originals and will not fit on the PCB but it's not hard to solder them togeather and run a pair of short wires to them.

The result? I ran the light for 30min continuous on high before I turned it off. No problems.
Finally my 2C P7 Mag is a sucess. :)

Sorry, no photos yet. I was in a hurry to assemble the light and I wasn't sure it would work in the first place.
I can now assure you it does :twothumbs
 

mitch79

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Do the new diodes require heatsinking? Does it just move the heating problem elsewhere?
No, I haven't got any heatsinking on the driver or replacement diodes.
The centre contact of the driver is soldered directly to the positive contact on the Mag "C" switch. The driver sits in free air.
No overheating issues since I replaced the diodes even with 30min+ runs on high.
 

spencer

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My driver is basically dead. It now only has a high mode and it doesn't last there for long. It stays in high for about a minute then flickers back and forth from high to low. Very annoying.
What are my options for a P7 driver? I'm running it in a 2D Maglite with 2x lithium ions. Should I try and return my old one?
 

ambientmind

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has anyone figured out how to make this a single mode board? I'd like to use der witchel's board, but its just simply too large for my application. or are there any other boards out there this size that will put out at least 1.8A off of 2 li-ions? i've been going crazy looking for something, but i've had no luck. thanks!
 

Hill

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MA
For a "D" Mag I highly recommend Der Wichtel's P7 buck converter.
I have a couple myself. Well made, don't get hot and just plain work.

Mitch,

Just saw your post. I am building a P7 in 3D host with DW's driver as well. Did you need to heatsink it? I will be using 9AA w/ NiMh cells = 10.8V

thanks,
Hill
 
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Oznog

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Well at $12 you can't argue with it on a price basis... but...

I have been doing design in a similar field and there's just no way that tiny electrolytic can absorb the ripple at this current level. Capacitance itself is meaningless, its series resistance will be so high it will fail to stiffen the input/output and just heat up (which will give the capacitor an astoundingly short life). Even the tantalum might be in trouble but without measurement it'd be hard to say for sure.

Actually there's some ultra-low ESR ceramics that you could maybe mod it with to bring the ripple way way down.

PIC16F629 has no ADC on it, so it probably can't do much to regulate its output.

On the Schottky- it may get hot, but that's not necessarily a problem. Oddly enough, they're actually MORE efficient when hot and they're not really prone to heat degradation as long as max junction temp is observed. So heatsinking won't help anything unless the diode is so hot it'll burn up the junction. Parallel diodes will help efficiency a little, but they won't share evenly. I think you're looking at efficiency gains on the order of 1% here, because you can only bring down the diode's Vf a little by doing this. Tohuwabohu hit on this the Vf may be 0.4v, but the LOWEST a huge Schottky could be would bring it down to a 0.3v drop. Which... isn't all that different. There are not really any higher current Schottky diodes in this size package and again it's not going to bring down Vf all that much.

Gotta say that even though there may be some dicey choices in this design (probably to serve you with a $12 driver), there are physical limitations even if we went with the best of components and still fit on a 17mm board.
 
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Footleg

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Ordered 3 of these drivers http://www.kaidomain.com/ProductDetails.aspx?ProductId=1866 just before Christmas and 3 P7 LEDs http://www.dealextreme.com/details.dx/sku.12721 to build my first high power LED lights. My driver boards appear to be the ones with only a single diode. This is covered by a white rubbery block which I assume is heat conducting to allow the diode to be heat sinked as suggested by earlier posters in this thread.

Fired the first one up last night, with the LED (mounted on a metal disk) stuck onto an old Intel Celeron CPU heatsink. Damn bright, and the whole heat sink got too hot to touch after a couple of minutes.

So my questions: How do you manage the heat in your maglight conversions? Surely a maglight body is not such a good heat sink as a CPU heat sink? So how hot do they get? Do they keep your hands warm without needing gloves on cold Winter nights outside?

How hot is it safe to operate these LEDs at? Despite holding the driver foam block on the heat sink, the entire driver board quickly got too hot to touch as well!
 

Aircraft800

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Ordered 3 of these drivers http://www.kaidomain.com/ProductDetails.aspx?ProductId=1866 just before Christmas and 3 P7 LEDs http://www.dealextreme.com/details.dx/sku.12721 to build my first high power LED lights. My driver boards appear to be the ones with only a single diode. This is covered by a white rubbery block which I assume is heat conducting to allow the diode to be heat sinked as suggested by earlier posters in this thread.

Fired the first one up last night, with the LED (mounted on a metal disk) stuck onto an old Intel Celeron CPU heatsink. Damn bright, and the whole heat sink got too hot to touch after a couple of minutes.

So my questions: How do you manage the heat in your maglight conversions? Surely a maglight body is not such a good heat sink as a CPU heat sink? So how hot do they get? Do they keep your hands warm without needing gloves on cold Winter nights outside?

How hot is it safe to operate these LEDs at? Despite holding the driver foam block on the heat sink, the entire driver board quickly got too hot to touch as well!

I believe that piece of foam or rubber substance is just for shipping safety, preventing the top of the board from getting smashed in the mail sorter unless something has changed since my order. That piece wasn't even attached, just poked threw with the wires. Do you have a picture? It may help identify it.

The Maglite body will get hot, the only way I see to manage it, keep it turned down to mid-level unless needed.
 

Footleg

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I believe that piece of foam or rubber substance is just for shipping safety, preventing the top of the board from getting smashed in the mail sorter unless something has changed since my order. That piece wasn't even attached, just poked threw with the wires. Do you have a picture? It may help identify it.

Sounds exactly like mine. It was a white rubbery block threaded onto one of the wires. I did think it seemed slow to transmit the heat from the board to my finger, although it did get hot eventually, so it is not completely insulating. I've started work on heat sinking the board with some RAM cooler heat sinks which I am cutting up to fit. I'll post pictures when I have got some. I chose these as they were cheap and included some heat sink thermal transfer permanent bonding strips in the pack. Cheaper than buying these separately from my local Maplin store anyway. I'm building into a box with a fair bit of free space, so size of the board is not a critical issue for me.
 

KnightRule

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I got the KD P7 Driver in March and it seem it's a new design from ones in September. There's no more thermal shutdown now. I ran it for 2 hours continuously, numerous times with no dimming in a Maglite 2c with no heatsink. It automatically shutoff when the voltage is too low (after 20 min of blinking). Although it get hot it work fine. I put a heatsink on it now though. I had an ealier version that runs on high for only 90 sec and then switch to medium (without heatsink).


[URL="http://www.postimage.org/image.php?v=gxFeyUS"][/URL]

It's available in 2 version: a 3 modes (high, med, low), and a 5 modes (low, med, high, strobe, sos). Both version looks exactly the same.
 
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KnightRule

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It's the same driver, just redesigned. Kaidomain didn't make a new page for the 5-mode. You don't which modes they will send you, so you might have to contact them directly and specifically state that you want the 3-modes or the 5 modes.
 

Ogg Vorbis

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I ordered a driver on 9-3-09, it's now sat happily in a 2C Mag. I checked the current in series with the LED and got 2.8A. I did find the board got very hot were the wopping great transistor was... so this is my solution!

DSC00689.jpg
DSC00690.jpg


DSC00692.jpg
DSC00693.jpg


+ Arctic Alumina...

It was powering a MC-E 'till i broke it (long story) but is now feeding a DSWOI P7 and i haven't had any troubles yet...

Just thought i'd share...

Dan
 

Aircraft800

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Wow Dan! That is an exceptional heatsink! Great design and clean work!

(Is that the 3 mode? If it holds up, I'll need one to replace the old one I have)
 
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Ogg Vorbis

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Thanks guys :thumbsup:

You may notice there are two holes and a little bit that i had to file out from the hole for the inductor, simply put i miss guessed the position of one of the LED wires :ohgeez:

And yeah it's the 3-mode driver, works great. I know it's not the most efficient one out there, but it works on 2x18650 (what i wanted for the 2C), and fits in the 2C mag, oh and it doesn't break the bank! (quick note as well, the sample i recieved has memory and turns on at the last used level)

I though i'd run it a little while today, i left it for 10 min on high with no contact, got quite warm but seemed stable. Now i can't wait for my Eagletac M2 to arrive :popcorn:

Dan
 

bstrickler

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Okay, I have one of these and installed it in my WF-1000L, but I have a problem

It's only single mode. It won't leave high mode (which is brighter than the original driver, which I fried, lol)
Also, it shuts off after only 30-60 seconds.

~Brian
 
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phantom23

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I got the KD P7 Driver in March and it seem it's a new design from ones in September. There's no more thermal shutdown now. I ran it for 2 hours continuously, numerous times with no dimming in a Maglite 2c with no heatsink.
Also, it shuts off after only 30-60 seconds.
Next change - thermal protection onboard again! And triggers even earlier...:faint:
 

bstrickler

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I bought the driver ~September-November of last year, when I was gonna make a P7 mag, but ran out of money before I could, so now its in the 1000L.

I hate the thermal protection circuit, because it cuts out so soon. What they need to do is just slap a heatsink plug on the driver like Ogg's heatsink, and charge like $1-2 more, so people don't have to worry about the damn heatsinking. Or just have it as an option, for the people who don't want it, because they're using it for something else.

Ogg, any chance you'll be willing to make more of those heatsinks? Just curious.

~Brian
 
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