Custom 4x18650 Mag (lots of pictures)

[spencer]

First of all, I did this build more than a year ago so I don't remember all of the details. I'll provide some details but I'm mostly going to let the pictures do the talking.

All pictures are clickable to fullsize images.

Host: 2.5D dual bored 4x18650 Mag from FiveMega
LEDs: 4x XP-G2 (I think somewhere in the range of R3 3D) on 10mm boards (Cutter)
Reflectors: Something from Cutter (Reginas? maybe?)
Heatsink: Custom
Driver: Maxflex at 1400mA (1300 maybe?)
Batteries: 4x 18650 (AW-3100mAh)

The host is excellent. It is dual bored, head is finned and scalloped, and body is milled. It has a charging jack which is a good idea but is quite high resistance due to a poor negative connection (small fault for how good the host is). I think there may still be some available but don't know for sure because I haven't been on here in awhile.


The first thing that needed to done was to modify the switch to momentary for the driver. There are details on how to do this elsewhere on this site so I won't go into detail.
Here is the switch assembly and modified base for the batteries. Note the grooves cut into the blue plastic for wire routing.


Holes drilled for wire routing.


More material removed to make room for wires.


Wires soldered and routed.


Everything in place.


Top view:


The heatsink was custom machined by my uncle. It was done in return for some labour. It was designed for the reflectors I used such that when the bezel was screwed down completely, it would put some pressure against the reflectors to prevent them from rattling.
Side view:


Top view:


It ended up being just a hair small so I put some copper tape on about half of it.


I made a centring jig for the LEDs. It was drawn to scale so the outside ring is the same size as the heatsink and the inner circles are the same size as the LED boards.
Printout glued to some random thin steel (I think it came from an old cookie tin):


Steel cutout with LEDs and reflectors:


All lined up. I used a piece of scotch tape around the outside to keep it from floating around.


Epoxied with Arctic Alumina:


Top:


Not certain why I don't have a picture showing it, (using the the below picture as illustration) but I cut small grooves on the bottom of the reflector just above and below the hole for running the wires off the board.


Maxflex with a custom heatsink.


I got a little anxious to assemble and didn't take any pictures during that step. Also, the epoxy on the heatsink for the Maxflex wasn't cured completely and it fell off during installation. I installed it anyway but since the Maxflex is being pushed to its limit, it does have thermal problems. Thankfully the board has built in protection so it throttles the output when it gets too hot to prevent damage. Maybe one day I'll open it back up and put it back on.

Down the pipe:


I don't know off the top of my head about runtimes or lumens but could do a little bit of math and figure them out if you are interested. I'll take comments and do my best to answer questions (if I can remember what I did).

Thanks,
Spencer

 

[Colonel Sanders]

Awesome build and I love the host. I have one exactly like it but I've only used it for various hotwire setups. I've never noticed any problem with the charger port, fwiw. The plug for it was always very snug...borderline too tight, so perhaps mine grounds better?

 

[spencer]

If your charging port is snug then it is very likely that it doesn't have the resistance problems that mine has. Mine is a little bit too big. It makes a decent enough electrical connection (can reliably get a good voltage reading from it) but its measured resistance is I think about 1 ohm. When charging at any reasonable current, too much voltage is dropped over the jack so the charger thinks the batteries are getting 8.4V but they aren't. I have remedied this by putting a quick clamp from the charging jack to the front of the light. This tightens up the connection and allows me to charge properly.

If I had to hazard a guess, I would say that our holes are likely the same size (drilled with the same bit) but due to manufacturing tolerances, I got a jack that was slightly smaller than yours. There isn't much that can be done about it and I don't fault the maker, but nonetheless, the issue is there.

Note: My jack isn't sloppy because I can't fit anything between (thinnest strand of wire I could find) to try to firm up the connection.

 

[Colonel Sanders]

The cool thing about this host is that you suffer a much smaller voltage drop when running due to halving the amp load per cell than with a typical two cell in series arrangement.

 

[MRsDNF]

I love your build and your honesty. A fantastic build. Thanks for sharing. Any chance of some night shots?

 

[ven]

Im not qualified in anyway to add anything constructive,but i am qualified in saying fantastic work,great pics there:thumbsup: Must give a real sense of achievement when you 1st light it up

Thanks for sharing:twothumbs

 

[spencer]

I'll see if I can get some night shots but might not be able to for awhile. Thanks for the kind words.

I forgot to mention the host is 2S2P.