Q about a DD P7 Mag. (Pics added)

[KeyGrip]

My brother has charged me with modding his 4D Mag. He wants an LED which is very bright, but still has practical runtime. This is going to be single level only. He doesn't speak Lumens, but I'm going to assume that 500-600 lumens will be "very bright" to him. It seems like I could get away with directly driving a P7 with four D cells, but I'm wondering if some sort of resistor is needed.

 

[Mettee]

Re: Q about a DD P7 Mag.

I started here, Stephan is a good guy to follow

http://www.candlepowerforums.com/vb/showthread.php?t=195358

There will be more to follow from just reading through this thread.

Drew

 

[KeyGrip]

Re: Q about a DD P7 Mag.

Those pictures are very helpful. It seems from that thread that DD is no problem, but I want to keep it around 2A so as not to tax the four D cells too much. What kind of hardware would I need to do that? Simple resistor? Board?

 

[DocD]

Re: Q about a DD P7 Mag.

Hi take a look at this thread http://www.candlepowerforums.com/vb/showthread.php?t=201981
this is the best driver IMO, and has a wide voltage range but be very carefull when setting this up you need a muilt-meter to set the forward voltage and amps hope this help's

 

[KeyGrip]

Re: Q about a DD P7 Mag.

That looks good, is that the simplest way to do it?

 

[Mettee]

Re: Q about a DD P7 Mag.

That is a simple way yes. but they cost a lot.

 

[StefanFS]

Re: Q about a DD P7 Mag.

The simplest way is 3 NiMH cells and direct drive. The other simple way is the 2800 mA drivers sold by KaiDomain, it's good quality for what it does:
http://www.kaidomain.com/ProductDetails.aspx?ProductId=1770
That one works with both 3 and 4 NiMH cells and it's a simple one mode on-off.


Der Wichtel makes custom drivers of high quality, custom work cost money. It's also a bit trickier to wire.

 

[lctorana]

Re: Q about a DD P7 Mag.

Well, assuming you really do mean "direct drive", and want it in a 4D Mag, and want to run the P7 at about 2A, then you will want to install, say, a 0.68 ohm, 5 watt resistor.

That assumes you're using NiCad or NiMH. If you're sticking with alkalines, I simply could not recommend direct drive at all. The voltage (and therfore the drive current) varies WAY too much, no matter what resistor you use.

 

[Mettee]

Re: Q about a DD P7 Mag.

I have not received all of my drivers for my P7 mods yet, so I got impatient and wired it direct drive with the 8 month old duracells that were in the light and it worked great. Not sure if it should have, but it does.

 

[KeyGrip]

Re: Q about a DD P7 Mag.

How many 8 month old Duracells are we talking about here, Mettee?

 

[Mettee]

Re: Q about a DD P7 Mag.

3 Ds .....they are dimming out today.

 

[KeyGrip]

Re: Q about a DD P7 Mag.

Thanks Met, that info helps. My brother and I have agreed to go the NiMH route eventually. For now I'm going to just run it on alkies to see if it actually works. Thanks again.

 

[Mettee]

Re: Q about a DD P7 Mag.

I am still on my first set of alk bats. They are still going pretty strong. They are a cheap knock off version of the duracell industrial version cells. I am going to get the tenergy bats soon.

 

[KeyGrip]

Re: Q about a DD P7 Mag.

Hey everybody. I just completed the mod and would like to thank you all for your help. Big thanks to StefanFS for the pictures and to Mettee for the feedback. My brother is duly impressed with the output.

 

[Mettee]

Re: Q about a DD P7 Mag.

very cool and you are welcome. I am new to this as well but I am getting into it. I am building a few with osrams now. Next thing I am going to try is a triple P7.

We should post up some pics in this thread of our builds/rookie builds

 

[KeyGrip]

Pictures!

Some quick pics:

"Home Sputtered" reflector:

And the beamshot it makes:

 

[Bobpuvel]

Looks sweet!!!:twothumbs

 

[Mettee]

I will throw up some of my pics later today when I can, looks sweet!

 

[irv_usc]

Re: Q about a DD P7 Mag.

Hey everybody. I just completed the mod and would like to thank you all for your help. Big thanks to StefanFS for the pictures and to Mettee for the feedback. My brother is duly impressed with the output.

just curious, but are you direct driving the p7 with 4 D alks?

 

[KeyGrip]

Re: Q about a DD P7 Mag.

just curious, but are you direct driving the p7 with 4 D alks?

I am, but it's only temporary until my brother gets a good NiMH D cell set and charger. I doubt the alkies will give more than ten minutes of full output.