Incan Modded 4D Mag - Super Cheap!

*Read this post in a Julia Child voice, it makes it more entertaining.*

What makes a great modded torch? Well, inexpensive parts and lumen output, of course!

I encourage you to experiment with these ingredients on your own--don't pay so much attention to the recipe, but try to feel how the parts will come together. Also, don't look into the business end of this thing once assembled, or you'll be compelled to take beta-carotene and Vitamin E for several weeks afterward! I speak from personal experience, ha!

Ingredients:

One of these:



And one of these:



And some chopping, wiring, etc. equals one of these!





Four 18650s in series, with some cardboard wrapped around them to fit the 4D Mag body, produce 16.6 V and roughly 4 A at the tailcap. The output is incredible! Of course, the beam isn't adjustable as the reflector, lens and bulb are all one unit, but it really does flood the heck out of half the house. For a total investment of $6 plus the cells (which I scavenged out of old laptop battery packs) I'd call this one a success. Up next is upgrading the stock switch to a 10 A unit for less resistance, 3/4" sch. 40 PVC piping and fittings for battery sleeves, and further modification of the tailcap spring to accommodate the longer-than-D-cells.

Bon appetit!

I may also find a way to better center the MR16 lamp in the Mag head--it's slightly (2 mm?) smaller in diameter than the inside of the head.

how many watts is one of those bulbs

50 W by the name on the package, but it draws 66.4 W from my pack. It's pretty bright....

I did this once with some steel pipe instead of a mag lite. Similar results, but mine all came from Wal Mart, even the batteries (Except the pipe). Click Later I ditched the duct tape styling and used better parts.

Edit: Be careful loaning these out. I killed 4 18650s in a (different) hotwire 50W flood lamp when my supervisor borrowed it. I didn't realize he'd put so much runtime on it until he mentioned how dim it was lately. The batteries wouldn't charge or hold voltage, and they (And the light) were scrap.

jkpq45 said:

Four 18650s in series, with some cardboard wrapped around them to fit the 4D Mag body, produce 16.6 V and roughly 4 A at the tailcap.

Click to expand...

Similar mods have been done by many other modders several time but of course more expensive version such as:

Polaris

Low resistance battery holders

MR16 drop in

And ....
Your bulb is a 50 watt, 12 volt, 2000 hours life. Is this true? If so, it should take (50/12=4.16)amps while it takes only 4 Amps which means bulb gets less than 12 volt which is way underdriven.
This means you have some heavy resistance in system including cells.
Your 18650 Li-Cobalt cells have about 1600mAh or less (if they are new) and you are asking more than what they can provide.
My suggestion is to use high current cells and fix the resistance of all connectors.
BTW, a 2000 hours life bulb can take much more overdrive.

FM, you don't think *most* of the 16.6 V reach the lamp? At 4 A, 16.6 V produces 66.4 W. Even at 80% efficiency, I'm still hitting about 6% overdrive on the bulb (maybe I'm wrong?)

Agreed that it can take a whole bunch more overdrive. I have a bunch of sub-C NiMH cells I'll build a pack out of next; this should give me more current handling ability.

jkpq45 said:

FM, you don't think *most* of the 16.6 V reach the lamp? At 4 A, 16.6 V produces 66.4 W. Even at 80% efficiency, I'm still hitting about 6% overdrive on the bulb (maybe I'm wrong?)

Agreed that it can take a whole bunch more overdrive. I have a bunch of sub-C NiMH cells I'll build a pack out of next; this should give me more current handling ability.

Click to expand...

Where do you get 16.6v: Measured open circuit, or estimating from 4.15v nominal voltage? I'm skeptical of those cells providing 4.15v per cell at 4A. Actually, I'd be stunned if 18650 LiCos like that do so.

Incandescents are all about voltage across the filament. That is the control for brightness, and the place to measure for output estimates. Unless you've got a voltmeter on a hot socket with a lit lamp, you don't know the voltage the bulb sees. My experience with asking too much of these cells with a 50W bulb is that you get about 12.8v at the socket on 4 18650s (3.2v per cell under over-heavy load) and it drops from there.

I see; it all makes perfect sense. Next time I light this torch I'll get my probes set appropriately and see what comes out the lamp.

I think this bulb as most of 2000hr life rated bulbs can easily stand up to 18v.. And they are bright (cheap too!)

I think Sc nimh may provide you more lumens and more runtime..but you will need at least 12 of them... And i don't think you can fit so many in a 4D form factor..

Correct, filippo.

If I moved to NiMH technology and wanted to retain the tube, I'd use AA or AAA.

14 AAs battery pack wil fit in an unbored mag tube and work just fine! Or you can use battery carriers..

AAAs are too small and can't provide acceptabele current/runtime!

do you have any pics of the actual cutting of the top ?

realone, do you mean you want to know how I modified the switch tower?

You're a wildman. I loved the bit about reading it in Julia Child's affected voice. Very amusing. Also amusing to me, is your use of four 18650s. After all, why settle for enough when you can have more? This reminds me of my 5D Maglite project. It's monumental. Like a pyramid in the works. Still not finished. Enjoy your light.