6PL + A19 + M61... it should work, right?

Dishonor39 · Dec 17, 2011

I was recently checking on my BOB making sure rations hadn't expired and batteries were good and such, and came across my Surefire 6P LED Defender. It sits in the BOB because any one of my other lights blows it out of the water in regards to efficiency, weight (prefer lighter), and output. I started looking around CPF to figure out what the hell I could do with it, and decided to just buy a P60 drop in for it, the plan was to find a $20 dollar drop in and go start dinner... well $100 bucks and an hour later I am now waiting for a Malkoff M61 and a Surefire A19 that I just ordered... The idea was to put 3 CR123 cells in the 6PL Defender body, with the A19, and then use the drop in. The drop in's voltage range is 3.4v-9v, so would that even work? Or would the voltage of 3 CR123s be marginally higher than the 9v cap? Never undertaken anything more than some 4.7s / Fenix lego'ing and a few Maglite drop in's. Any help would be appreciated. Thanks!

SunStar · Dec 17, 2011

The Malkoff M61 runs well on 2 or 3 cells. So now you have the option of adjusting the runtime you need according to use or carry preference. For BOB purposes, gearing for 3 cells is probably best. Be sure to add a few spares as well.

You are Good to Go Sir!

Kestrel · Dec 17, 2011

The Malkoff M61 & three CR123's should be just dandy. In fact, three cells will actually provide ~5% more stored energy than using the cells in pairs of two due to the lower current drain (at the overall higher voltage of the cell stack) providing greater cell efficiency - I ran the numbers a while back based on test data.

In other words, using two sets of 3xCR123's will provide you ~5% more total runtime than three sets of 2xCR123's.

And of course, in a roadside / BOB emergency, who wants to have to do cell changes more often than they have to, anyhow?

Furthermore, with 3xCR123 internal capacity in your body+extender, you have the capability (in a true emergency) to run 2x Alkaline AA's for ~10-20 lumens or so for a long, long time. Can't really do that with a 2xCR123 body like the standard 6P.

Dishonor39 · Dec 17, 2011

Awesome, thank you both for your responses. I had never considered the 2 x AAs either, good to know. I currently run Eneloops in all my AA / AAAs charged off a Maha C9000 and was thinking about starting to get into LiIon recharging as well. Would using 3 AW RCR123As be possible / safe? I need to find me a comprehensive thread on getting started with LiIon charging.

Edit: Any opinions on using 2 x 14500 cells? What could I expect from that setup?

Kestrel · Dec 17, 2011

Dishonor39 said:
I had never considered the 2 x AAs either, good to know. I currently run Eneloops in all my AA / AAAs charged off a Maha C9000 and was thinking about starting to get into LiIon recharging as well.

Just a FYI, 2xAA eneloops will barely fire up the Malkoffs, you really need the slightly greater voltage of 2xAA Alkalines to get any usable output.

Would using 3 AW RCR123As be possible / safe? I need to find me a comprehensive thread on getting started with LiIon charging.

3xRCR123's is definitely way beyond spec for many dropins including the Malkoffs. A couple of years ago it took someone an entire month to kill an M60 with 3xRCR123's, which says something for the robustness of the Malkoff drivers IMO. Instead you would want to use 2x 17500's, more capacity / more runtime / more reliability for the same overall length. Another topic entirely though, and not a great setup for car/BOB use though.

Edit: Any opinions on using 2 x 14500 cells? What could I expect from that setup?

Not worth bothering about, 2x17500 is an extremely popular configuration for the stock bodies, although some <ahem> use 2x18500 in bored three cell SF bodies for even greater runtimes.

TXflash · Dec 17, 2011

You could also run a M31L off two AA L92 lithiums for even better runtime. Get yourself some 17mm-14mm AA adapters and have the swiss army knife of flashlights. Two AA Lithiums will store for 10 years in your BOB and not leak like alkalines.

BTW, I am planning doing exactly this for a home emergency light but probably in a G3 body.

BIG45-70 · Dec 17, 2011

I will be running a similar setup as soon as my 9P arrives. I'm going to run an m61llw in it but going the rechargeable route with a pair of 17500's.

pjandyho · Dec 18, 2011

Just curious, does your 6PL Defender come with a removable drop-in? I thought Surefire had the reflector and LED built into the bezel? Is yours the earlier model of the 6PL Defender?

Dishonor39 · Dec 18, 2011

Yea, I have the older 80 lumen model. It's something like... 5 years old maybe? The emitter and reflector are a single unit that is separate from the strike bezel / head / lens. I believe the bezel is threaded on, but must be on there with some loctite, I can't get it off without risking damaging the light.

Edit: I have decided to go with the 6P LED Defender, the A19 extender, and have gone back on the fence for the drop in. I am planning on running 2x 17500s bedside, with the CR123 primaries in the BOB, with some sleeves so I can run AA if I have to. For the drop in I can't decide between the thrunite xpg, xml, or the Malkoff Neutral High or Standard Low, not Low low.

kelmo · Dec 18, 2011

The M61L is a better choice for a BOB. 170 lumens for 5 hours with 2 CR123s. It is plenty bright with great runtime. Get a Surefire FM34 diffuser to give you a nice flood option. That will increase its utility and protect the lens in storage. A SC1 to store the P60L and extra batteries would be the final touch.

BTW welcome to CPF!

pjandyho · Dec 18, 2011

Dishonor39 said:
Yea, I have the older 80 lumen model. It's something like... 5 years old maybe? The emitter and reflector are a single unit that is separate from the strike bezel / head / lens. I believe the bezel is threaded on, but must be on there with some loctite, I can't get it off without risking damaging the light.

Edit: I have decided to go with the 6P LED Defender, the A19 extender, and have gone back on the fence for the drop in. I am planning on running 2x 17500s bedside, with the CR123 primaries in the BOB, with some sleeves so I can run AA if I have to. For the drop in I can't decide between the thrunite xpg, xml, or the Malkoff Neutral High or Standard Low, not Low low.

I think you will be well served with the Malkoff M61L. Tough and durable for a bugout situation.

Dishonor39 · Dec 18, 2011

Anyone know how running the M61L with 2x 17500s would compare to running it with 3x CR123s? What would be affected and how? Run time, output, output curve?

Kestrel · Dec 18, 2011

Dishonor39 said:
Anyone know how running the M61L with 2x 17500s would compare to running it with 3x CR123s? What would be affected and how? Run time, output, output curve?

Looking at the test data, 2x17500 LiIon rechargeables have very very close to the same total capacity as 3xCR123 lithium primaries, so for the most part you can expect the same regulated output & runtimes. However, the two main differences would be:

You can most often start your flashlight usage with topped up cells when using LiIon rechargeables - with intermittent usage, you'll often not know when to retire the three CR123 primaries that are in the light prior to using them in the field. The effect of this is that you will get greater regulated runtime with the LiIon configuration since those cells can be repeatedly topped up before each use.
However, the protection circuits in the 17500's will shut off the light without warning upon cell depletion. This compares unfavorably with the long, gentle decline in output that you will get from running the lithium primaries to complete exhaustion of the cells.

Again, since you were initally discussing BOB / backup usage, I very much recommend against using LiIons for a light that gets used only seldomly (and mostly in emergency situations when reliability is at a premium). I happily use rechargeables (mostly LiIons) for 99.9% of my overall flashlight usage, but emergency lights should be loaded with CR123's, Energizer Lithium AA's, or Eneloops IMO. Many others here will agree on this.

Hope this helps,

Dishonor39 · Dec 18, 2011

Very valid point. I hadn't considered the sudden death nature of the LiIon. Well it is settled. Parts are ordered. Thumbs are twiddling. SF 6P LED Defender, SF A19, Malkoff M61L (my first Malkoff), and another box of CR123 primaries. Thank you everyone for your help and shared knowledge, and thank you Kestrel for providing some very specific data in an easily understood fashion. I'm going to go hurry up and wait.

Kestrel · Dec 18, 2011

Happy to help.

And one day you might pursue your BOB concept to its ultimate conclusion (a true dual-fuel setup), lol:

The Malkoff M31 is a perfect match for 1xCR123 or 2xAA NiMH, and can even run 2x Alkalines in an emergency, albeit for relatively short runtimes. The capability of ~240 OTF neutral lumens for 12+ hours is pictured above (not including the option of approximately 500 hours @ ~5 lumens or so from the 5mm LED / P60 assembly. Since this pic was taken I have also added extra cells as well as a SolarForce multi-mode low-voltage dropin to the above kit for more flexibility.

6PL + A19 + M61... it should work, right?

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