???Multi Function Driver Heat Sink/Battery+ terminal???

[Aepoc]

I just completed a sub-1D tri-XML Mag mod and had to provide a heat sink for the driver (kaidomain's 8X7135). Needless to say, the body that I'm using is very short and I ran into some troubles regarding space for components and heat sinking:

I had to modify Fivemega's 3x17670 battery pack by removing the nub on the negative terminal.

I had to remove the spring and provide a solder bead for electrical connection to the tail switch

Lastly and most importantly I had to permanently attach a wire to the positive terminal of Fivemega's pack.

This permanently attached wire makes recharging quite a hassle because it's attached to the positive portion of the pack which screws on to hold the whole pack together. Recharging requires holding the cap stationary, since its wired to the light, and applying torsion to the 3x17670's and the negative part of the battery pack...

There's very little clearance (~.02") between the positive terminal of Fivemega's pack and the copper slug used to provide heat sinking for the driver. The permanently attached (green) wire is getting pinched between the two and I fear it will need to be replaced soon. The whole setup would be much more user friendly if I could solder the green wire to the copper driver heat sink and provide a ~.02" solder bead for the connection to the positive terminal of the battery pack. This would effectively eliminate the need to have a wire permanently connected to the pack and make dis assembly for charging a whole lot easier.

Okay hopefully that wasn't too confusing... Here's my questions: Would the proposed setup subject my cells to an unsafe level of heat? Would adding a charge to the driver heat sink be just asking for a nasty, damaging short? Are there any issues which may arise that I haven't considered?

Any input in the form of warnings, suggestions, experiences, or alternate designs would be greatly appreciated.

Thanks in advance!

 

[Slickseth]

Rather than chop up an expensive battery holder, I think I would just buy another mag body and cut it to the proper length. Mag bodies are cheap. Modifying and possibly ruining the other components could be much more expensive. Just my opinion.

How much current are you planning to feed the emitters? I'm not sure that that 3x17670 pack will be able to handle running 3 XM-Ls at their fullest (30 watts). But i could be wrong on that one. Again, just my opinion/constructive criticism.

 

[Aepoc]

The holder has already been chopped... Believe me, I had my apprehensions about doing this but it worked out well. Mag bodies are cheap, but chopping and finning them can get expensive; more expensive than the battery pack. Anyway, would I damage the circuit or LEDs by using the driver heat sink as a contact for the positive battery pack terminal... anybody?

 

[Sway]

The holder has already been chopped... Believe me, I had my apprehensions about doing this but it worked out well. Mag bodies are cheap, but chopping and finning them can get expensive; more expensive than the battery pack. Anyway, would I damage the circuit or LEDs by using the driver heat sink as a contact for the positive battery pack terminal... anybody?

Use a DMM to see if the driver is grounding to the heat sink if so NO, the few driver boards I have worked with have a negative ground to the areas that can be sinked for heat dissipation this could cause a short and catastrophic failure....don't think I would advise it.

Later
kelly

 

[Aepoc]

When I attached the driver sink, I was careful to be sure that it only made contact with the black plastic transistors (not sure if transistors is the right term). I removed some copper on the heat sink where it came close to contacting other parts of the board and I placed some electrical tape on all possible contact locations before epoxying the heat sink to the driver.

The ground from the driver is connected to my LED heat sink so it is negatively charged. There is one location where the driver heat sink is close to the LED heat sink... (.1-.2") Nothing inside should move unless the epoxy gives way, so I can't foresee any unwanted shorts. That being said, if I decided to do this, I would be sure to insulate this location with electrical tape...

I know that it isn't an ideal design, but aside from dealing with this pain in the a** wire, I can't see any other solution. I fear that I will have to replace the wire often as it gets pinched every time I remove the battery pack for charging...

 

[Aepoc]

The light seems to be working fine for me right now, but if I have to replace that wire, it looks as though I will be going this route... I don't see any charge on the Driver heat sink itself...

 

[Icarus]

Rather than chop up an expensive battery holder, I think I would just buy another mag body and cut it to the proper length. Mag bodies are cheap. Modifying and possibly ruining the other components could be much more expensive. Just my opinion.

I would also suggest to use a taller body and use a one piece light engine (pot the driver completely in the cavity at the back of the LED heatsink and add an insulated positive battery contact on top of it). :wave:

 

[Aepoc]

Thank you guys for your input. I am building one of these mods for my father and this will indeed be using a larger Mag body. This current light setup however is using a body that I already had just laying around... Mac made this shorty Mag body for me years ago and when the single SSC P4 that was in it died, I thought it the perfect opportunity to create my first tri LED mod. As stated before I know it's not an ideal design, but as of right now I have already invested the time and money into this shorty Mag mod. The light is together and works just fine, there are just a few quarks and less than Ideal design features that I would like to correct... If it means taking apart the whole light and starting from scratch, I would rather deal with quarks

The new tri-xml will be using a 3.25 Mag C body to eliminate the spacing issues and the required use of the cell pack. My father has no patience to deal with the problems of my shorty light, so all of your suggestions will be accounted for. Unfortunately I haven't come across any good suggestions to deal with the problems of my shorty tri-xml copper Mag (pictured above)...

Please, if anybody can think of anything let me know!