Which direction to take my first mod-a-mag?

Y halo thar!

I recently bought my first 'grail' light. It's nothing fantastic, but it's something I've always wanted: a 1D maglite. The trouble is, I can't decide which direction to take it.

I've been looking at either going with a Malkoff dropin, or doing the terraLUX 140 (claimed) lumen pr2 replacement. Power is going to be a 3xAA to D adaptor run in series, providing 4.5volts. I'm going to be using the lithium AA primaries, since I haven't QUITE gotten to the stage where I'm dropping dough on chargers, and getting into the whole recharging thing. One step of the addiction at a time, please.

As of this point, I'm leaning towards the Malkoff dropin, but I have a few questions. I'd obviously have to do the dropin for the 3-6D mag, as the 2-3D is only rated to take 3.3volts. While brighter at over 200 lumens, it's the runtime that I worry about.

Am I still going to see several hours of solid lighting? or am I going to have better luck sticking with the terraLUX for good runtime?

I'd like to see several hours of runtime, but could deal with a minimum of 2 hours of solid performance.

Lastly, is the sandwich shoppe still shipping regularly? I'm looking into going with one of their MOP reflectors, if still available. Otherwise if there is something else you would suggest, i'm two ears! (being all ears would make it hard to type. )

Thanks!

Presume your 1D is custom cut down already? In which case did you cut it yourself or if not, was it not already running a LED upgrade of some kind?

Personally I'd probably not go for the TerraLUX if you are going for just a simple drop in like this. The Torch Site (UK based) sell an XP-E and an XP-G R5 drop in of similar style and design, both putting out more lumens and better performance than the TerraLUX with no additional downsides. http://www.thetorchsite.co.uk/TTS-3WCR90_CNC_XPG-R5_LED.html

I've got both the XP-E and XP-G R5 and they are impressive upgrades from a stock incan MagLite. Of course this design of drop in will have heat issues as there is little heat sinking, the drop ins do have "Temperature Auto Control Power" so they'll drop lumens to reduce heat on long run times.

The Malkoff has much better thermal management, but costs more. But it is the better setup.

As for run times, I don't know, someone more clever than me will be able to work it out I'm sure. The only thing I'd say is, lithium primaries have a lot more capacity than NiMh AA's, so if you switch to Eneloop rechargeable, expect a dip in run time. Also NiMh's are only 1.2v each, not 1.5v, so you're voltage will be 3.6 rather than 4.5v. Lithium primaries are great, but I suspect will get pricey to run after a while, even more so when you consider buying a pack of Eneloops and charger is so cheap.

That said, I'd have thought running a single 26650 li-ion would be the way to go with this setup.

Any other thoughts on this from anyone?

Hummm, 2 hours runtime off 3 AA batteries. So ~ 1-1.2A to the LED should be good. Which version of the Maglite do you have?

I have a 1d, cut down from.... something. probably a 2d?

219 views and 2 responses.

you guys rock.

thanks at least to the two who contributed.

Which version? Is it an old version without the D in the serial number? A new cutdown MagLED (which version of the MagLED, Luxeon emitter, Luxeon Rebel, or Cree?)?

Also, 3 NiMh rechargeables would work well too, and be cheaper in the long run.

How about one of the deal extreme modules. You might need to step up to lithium batteries to make it work. I used the single mode with the 5 R2's. It's pretty damn bright for $27.00

If you check Silverfox's alkaline battery shootout thread, he has 0.5A and 1A discharge graphs for the Energizer AA Lithiums. it looks to me that you would be best served limiting current draw to 1A or less.

At 1A draw, the Energizer lithium cells can hold about 1.3V under load for around 60 min and 1.2V for around 120 min. Under load, the cells look like they immediately sag to about 1.35V.

At 0.5A draw, the Energizers predictably do better. They immediately sag to about 1.4V and hold above 1.3V for about 270 min.

I don't know anything about the Terralux product.

An important question on using the Malkoff 3D-6D drop-in is the minimum voltage needed to stay in regulation. The AAs have enough energy to hit your run time goal. For example, at 1A draw, Silverfox's data says the Energizer lithium has 3.7Wh. 3xAA gives a total of 11.1Wh. The Malkoff XP-G has a 1A drive current, according to the Malkoff web site. If we assume a Vf of 3.3V, that gives a power draw of 3.3W. 11.1Wh/3.3W gives a calculated run time of about 3 hours.

The problem is that you might not be in full regulation for all of those 3 hours. It depends on the battery current draw, the battery voltage sag, and the Malkoff driver voltage requirement to stay in full regulation.

Let's assume the following:

driver efficiency = 85%
Vbatt (per cell) = 1.3V; therefore, Vbatt (total) = 3.9V
Vf = 3.3V
If = 1A

Thus, 0.85 * Ibatt * 3.9V = 3.3V * 1A and Ibatt = 1A. Even if Vbatt (total) = 3.6V, Ibatt = 1.1A. So we can use Silverfox's 1A discharge curve for the Energizer lithium AA. If the Malkoff requires 1.3V per cell (3.9V total) to stay in regulation, then you will fall out of regulation after about 60 min. If the driver stays in regulation down to 1.2V per cell (3.6V total), then you could stay in full regulation for about 2 hours.

I would assume that you are ok since the Malkoff 3D-6D product is claimed to run on 3xD alkalines for the rated performance specs (6+ hours in full regulation), which means the driver can hold regulation for a low Vbatt.

Silverfox's alkaline shootout data shows D alkaline capacity under 1A load to range from about 5 Wh to 8.3Wh, depending on brand. Six hours of run time at about 3.3W draw gives ~20Wh total energy required, which looks consistent with what 3xD alkalines can supply. However, to deliver that amount of energy, cell end voltage has to be around 0.8V under load, or about 2.4V total. That suggests that the Malkoff driver is a boost-buck driver that can run in full regulation from about 2.4V up to 9V.

However, the Malkoff web site cites a driver voltage range of 3.4V to 9V.Even the best D alkaline that Silverfox tested would drop to about 0.9V per cell, or about 2.7V total, after 6 hrs. So there seems to be a discrepancy somewhere.

Also, Silverfox's alkaline shootout thread shows that Duracell and Energizer D alkaline cells fall below 1.2V under 1A load by 100 min. The Energizer AA lithium performance under 1A load actually looks better than for D alkalines, at least until the AAs run out of gas.

now THAT is some data! thanks for the awesome post. looks like i have some research to do!


thanks guys!