Question about the Elzetta ZFL-M60 (3-cell)

KeeblerElf · Dec 8, 2012

Greetings! Long-time lurker and flashaholic, first-time poster on CPF!

I'm considering the Elzetta ZFL-M60 (I could go on about the reasons for this choice, but suffice it to say I've seen plenty of videos online and read many CPF endorsements of the light). I like the extended run time from the 3-cell option, but I need the option to use rechargeable cells with my lights (I'm a fan of "guilt-free lumens"). But Elzetta's site explicitly says not to use 3 x 16340 because of the high voltage. What I'd like to know is: does anyone here have experience in or knowledge about using 2 x 17500, or some other combination of rechargeable cells with the 3-cell ZFL-M60?

I saw someone propose the 2 x 17500 option in another thread, but I never saw a response to the suggestion. I'm not an electronics expert, but it appears that this would be within the voltage tolerances of the light. I'm not sure if the batteries would fit in the tube, as it is my understanding that the 17500's are about 1mm larger in diameter than the 16340's. If it matters, I don't anticipate using the light for critical or tactical applications.

I've done a lot of searching for this question, but most information about the ZFL-M60 seems to be about the 2-cell model. My apologies if I've simply missed the answer!

Erzengel · Dec 9, 2012

In their FAQ section they state:

Will the Elzetta ZFL-M60 Tactical LED Flashlight run on rechargeable RCR123 batteries? 2-Cell Models may be operated on RCR123 batteries, but 3-Cell Models should not use these batteries as the voltage may exceed the maximum limit of 9 Volts.

Two 17500 have a peak voltage of 8.4V, therfore You should be ok from the electrical point of view. I don't know, if the 17500s will fit.

twl · Dec 9, 2012

2x17500 will fit.
It's a close fit, but they fit in mine.

BIGLOU · Dec 9, 2012

Someone should bored out a 3 cell and use 2x18500s. That would be nice with a M91 set up.

tobrien · Dec 9, 2012

welcome to CPF! have fun with your future Elzetta, I want one REAL bad haha

KeeblerElf · Dec 10, 2012

Thanks for your replies, and for the welcome to CPF!

So it sounds like the 2 x 17500 option both physically fits and should be safe from an electrical perspective. Thanks for taking the time to check! Out of curiosity, twl, were you using AW protected 17500's? I'm not sure what kind of variances there are in the size of 17500's in general, so I want to make sure I don't screw something up should I go with this option.

Perhaps this is a question for the battery section, but would 2 x 17500, each at 2200mAh mean I should expect nearly double Elzetta's stated run time, since they were presumably using 3 x CR123A, each at 750mAh (assuming identical output levels)? Should I expect the same level of output using the 2 x 17500 as compared to the primaries? I know some lights ramp up their outputs in accordance with the voltage of the cells being used. Ideally I could find some graphs like those of selfbuilt to compare outputs and run times from various sources, but I haven't been able to find much information about using the Elzetta with rechargeable cells.

Thanks for any additional info.

twl · Dec 10, 2012

No, the 2 17500 batteries gives 8.4v, and the 3 CR123 primaries give 9v, so it is nearly the same voltage.
The batteries in series add voltage, but the current capacity stays the same as one, so it stays at 1100 mah which is about 300 mah less than a typical set of primaries, so your runtime will be a bit less than with the 3 primaries.

The output brightness will be the same because you will be in regulation the whole time with the 2 17500 batteries.
You'll have about 20% less run time with the 17500, but you can charge them back up when you want.

The Elzetta has springs on both ends which can accommodate some small variations in battery sizes.

Elzetta doesn't promote the use of rechargeables in the light because it is also considered a weaponlight, and rechargeable batteries with protective circut boards on them might be damaged by heavy recoil and not work when you need them.
So, for tactical lights like this and Surefire too, they recommend the primary batteries for this reason.

If you want to double the run time, you'd be better off to buy the Malkoff MD2 head(with a Hi/Lo Ring if you want 2-modes) with the MD4 body and run 2 x 18650. If you choose 3100 or 3400 mah 18650, you will have double the run time or even a little better.
The Malkoff bodies are already bored for 18xxx size batteries.
Or you could choose the MD3 body, and use 2 x 18500 for the same run time as using 3 x CR123.

Then you can put whatever Malkoff drop-in you want into it, and if you want the M60 that comes in the Elzetta(which is a Malkoff design anyway) you can buy one from Elzetta, or get a used M60 off the CPFMP. It will go right into the Malkoff MD2 head with just the same fit as it has in the Elzetta.
It would be the same basic thing

KeeblerElf · Dec 10, 2012

twl said:
No, the 2 17500 batteries gives 8.4v, and the 3 CR123 primaries give 9v, so it is nearly the same voltage.
The batteries in series add voltage, but the current capacity stays the same as one, so it stays at 1100 mah which is about 300 mah less than a typical set of primaries, so your runtime will be a bit less than with the 3 primaries.

The output brightness will be the same because you will be in regulation the whole time with the 2 17500 batteries.
You'll have about 20% less run time with the 17500, but you can charge them back up when you want.

The Elzetta has springs on both ends which can accommodate some small variations in battery sizes.

Elzetta doesn't promote the use of rechargeables in the light because it is also considered a weaponlight, and rechargeable batteries with protective circut boards on them might be damaged by heavy recoil and not work when you need them.
So, for tactical lights like this and Surefire too, they recommend the primary batteries for this reason.

If you want to double the run time, you'd be better off to buy the Malkoff MD2 head(with a Hi/Lo Ring if you want 2-modes) with the MD4 body and run 2 x 18650. If you choose 3100 or 3400 mah 18650, you will have double the run time or even a little better.
The Malkoff bodies are already bored for 18xxx size batteries.
Or you could choose the MD3 body, and use 2 x 18500 for the same run time as using 3 x CR123.

Then you can put whatever Malkoff drop-in you want into it, and if you want the M60 that comes in the Elzetta(which is a Malkoff design anyway) you can buy one from Elzetta, or get a used M60 off the CPFMP. It will go right into the Malkoff MD2 head with just the same fit as it has in the Elzetta.
It would be the same basic thing

Thanks for the detailed response!

I was having a little trouble understanding your first paragraph, until I realized I was using a 750mAh capacity for primary CR123A cells, rather than the typical 1400mAh (and a 2200mAh capacity for the 17500's instead of an 1100mAh capacity)! That makes much more sense now

luceat lux vestra · Dec 11, 2012

:welcome: Elzetta flashlight are very cool.

and I am currently trying to resits :broke:

Question about the Elzetta ZFL-M60 (3-cell)

KeeblerElf

Enlightened

Erzengel

Enlightened

twl

Flashlight Enthusiast

BIGLOU

Enlightened

tobrien

Flashlight Enthusiast

KeeblerElf

Enlightened

twl

Flashlight Enthusiast

KeeblerElf

Enlightened

luceat lux vestra

Enlightened

Similar threads

Latest posts