Mad D 5W and Focus Plan

[Bunk3r]

*Mag D 5W and Focus Plan -(mods please fix the title if you can)

Firstly hi this is my first post!


I started looking at doing a drop in ebay 3w led upgrade, but price was an issue, but figured I could make my own much cheaper. I realised the danger of making my own would be insufficient heatsinking, a bit of googling and I found the heatsinking was a universal problem and not all drop ins are the same and then google brought me here: and I found that the heatsinking on even the official drop in replacements isn't upto scratch.

On here pepole seam to go two ways, live with the drop in power when it heats up (after all it is still bright) or sacrifice the focus mechanism and build a big heatsink. Well I want both power and the ability to focus.

I have a 2D and 3D maglite, but I would rather mod the 2D as its smaller and more convenient. I was first looking at 3W LED's, but I see there are 5W's now so that would be the obvious choice! My first question is: can two D's provide the 1.67 Amps (or so not inc inefficiencies etc) needed to power 5W? or shall I use my 3 cell (3D's at 1.1 Amps or so).

I will make my own boost circuit (/buck if I use the 3D) (by make my own I mean copy off a datasheet and put the parts together, rather than buying a 'module').

For the heatsinking this is what I plan:
(Original Drawing taken from idleprocess post, modified to show what I plan)

side view:

Top view of heatsink, showing chopped bulb holder

Key:
Orange: copper (or alu if I cant get hold of copper)
Grey: Alu
Yellow: LED
Blue: Boost/Buck
Green: screws.
Pink: thermal conductor pad

Principle:
1)The cam on the maglite is shortened and a new screw is put in place to activate the cam. the two screws stop the new inners from rotating when the head is turned.
2)The led is mounted on a piece of copper (or Alu) that is inplace of the bulb body.
3)A heatsink is lower down some cutting away of the existing bulbholder is needed to allow this to work (see top view as its not shown properly in the side view).
4)The Boost/Buck will reside somewhere in the void shown in the picture (its form may differ greatly).
5)the two copper bits at the sides are attempts at bushes to transfer the heat to the mag body as the main heatsink will be cut very roughly (no lathe etc)–don't know if there a good idea or not!
6)To electrically isolate the LED I plan on using a thermal conductor pad and screw mounts, as shown in pink. Alternatively I may put some epoxy on let it set then reglue,



what do you pros think?

(edit: i have now put down the lux III datasheet and picked up the LUX V and realised the lux V needs around 7V and 700mA so i will need a boost either way if using this. also the P4 LED mentioned below looks interesting)

 

[Daekar]

Great idea! Unfortunately somebody beat you to it... check out this website:

http://www.malkoffdevices.com/index.php

It's run by a forum member who does top-notch work at creating well-heatsinked dropins for maglights, both C and D sized. They push about 240 lumens for a good long time even with regular alkalines... here's a quote from Gene's website:

"The light is focusable. It operates on 3 easily available D size alkaline batteries. The runtime is 6+ hours at the rated output it will continue to operate at reduced output for several more hours."

If you're interested in getting one, I'm sure Gene would be happy to oblige!

 

[joedm]

I like your idea.

I currently have a modded 4D using Litemania's heatsink but it does not have focusing via the cam only via screwing in and out of the head.

From looking at the Malkoffdevices drop in, it does not look focusable via the original CAM action.

 

[Bunk3r]

Great idea! Unfortunately somebody beat you to it...

i dont mind not been the first! i dont claim to be Im sure someone else has done it. allthough on the one linked i dont think it uses the cam action as it tells you to cut it off http://www.malkoffdevices.com/shop/index.php?main_page=product_info&products_id=15

focusing via the cam only via screwing in and out of the head

-i had omitted to realise that without the cam you can still focus by screwing /unscrewing! -how many rotations does it take? -maybe i should live with it like everyone else, or at least that can be plan B when i mess up my mag!

 

[ace0001a]

Yup without the camming mechanism, it does take more turns. Personally I don't feel that is an issue. Just about all other focusable flashlights out there don't use a camming mechanism and they get the job done. As we all know, with the mechanism is place, there is just no thermal path to the aluminum body. When you're driving these LEDs with an amp or more, having a thermal path to the body is a must. Unless you've got a huge chunk of metal holding the emitter in there, there really isn't a choice...otherwise you end up cooking the LED and therefore reducing the life of the LED.

 

[Bunk3r]

I'm tending towards modding the 3D now, as I am going to buy a small led flashlight (been bitten by the bug) for backup and when I don't need a big one, so my big one may as well be bigger with more capacity and baton capabilities, also doing a boost circuit is more of a pain and more inefficient.

For the LED I decided against the 5W Luxeon as the 4chip in one design means you cant get a good focus, and the SSC P4-U are much more impressive in terms of efficiency, and are $6.99 at http://www.dealextreme.com so it would be daft not to. I also noticed that dealextreme do a 4 pack of regulators http://www.dealextreme.com/details.dx/sku.3256 for $6.44 and there are these http://www.dealextreme.com/details.dx/sku.4255 , so it doesn't really seem like there's much point in building my own at this stage! I don't mean to be a walking advert for dealextreme, I found them from searching on here and I am limited with been in the UK but they do free shipping, feel free to point me elsewhere, but as I say bare in mind I am in the UK and postage costs.