Would a Fenix TK60 on 3x Energizer Lithium AA batts (in converter sleeves) be safe?

Hi, I really liked my TK50, but wanted some more ...power. I know that e2 lithiums are pretty tough batts, but I do not want to destroy a new light. What do you wiser tech people than myself think about using 3x AA lithiums (1.5-1.7v) not 4.2 cells (in AA-D adapters) in a Fenix TK60? (would be the brightest 3AA light ever!)

woodrow said:

Hi, I really liked my TK50, but wanted some more ...power. I know that e2 lithiums are pretty tough batts, but I do not want to destroy a new light. What do you wiser tech people than myself think about using 3x AA lithiums (1.5-1.7v) not 4.2 cells (in AA-D adapters) in a Fenix TK60? (would be the brightest 3AA light ever!)

Click to expand...

It's been ages since I used D cells but I don't think it would work.

IIRC the TK50 is 2xD? And if D cells are 1.5v like I remember, and since L91's are 1.7v nominal, then you're looking at over 4 volts in a light that really should only be getting 3 volts. You might very well the emitter, and that would be a shame.

B0wz3r, thanks for the reply! I am hoping that since the TK60 can run on 3 or 4 D cells (1.2x4=4.8nimh or 4x 1.5alk=6v vs. 1.7x4=5.1 aa liths) it would be safe. I am slightly worried about the amps to the lithium AA cells though.

Clarify?

The TK60, with extension, holds 4 D cells. A D cell is 60.5mm +- 1mm. An AA is 50 +- 0.50 mm. So you can put 5 AA where you once had 4 D cells.
Is this what you wanted to do?

AA cell in a C adapter (check Amazon). Then put some sort of carrier to prevent misalignment. Traditionally in a Maglite, you'd get a piece of PVC as your sleeve. (and you could drill some holes in the PVC for lightness)
Now onto the voltage issues. The initial voltage & the working voltage.
Even Energizer L91s will sag under load. (and Energizer EA91s will sag more)
HKJ tested a TK41 (working) up to 7 volts. So you should be fine even with L91 on turbo.
So we need to know if the TK60 will be safe with a transient initial voltage of about 8 volts.
and with an 'off' voltage of 8.5 (used) -9 volts (new)

OR do you want to use 3/4 [with TK60 extension] (3x AA) parallel adapters?
If you use only 3 parallel adapters, there would be about the same voltage compared with using just 4 D alkalines.
If you use 4, there is only a minimal increase in working voltage compared with using 4 NiMH.

I have used AA's in D size adaptors before in a maglite running a TLE-300. Not the same thing by far, but the thing I found was that the cells still get warm (AA's warm up quicker than D's, probably due to shear mass) but the AA's don't contact the lights metal tube at all. So after running them for about 5 minutes, taking one out of the adaptor, the cell felt considerably hotter than I was comfortable with.

the ones I used were from DX and could hold 2xAA in parallel (2x capacity, 1x voltage) and had 4 of them in the light.

Sorry for not being clear, and thanks for the tips. I was thinking of using 3xAA lithium's in the TK60. Tolkaze, your post in particular kinda makes me nervous about trying it.

Well, if you are going to use just 3 AA to power the TK60, you can use low/medium/high. Turbo isn't going to work. SOS & Strobe will work too.
But over 3.5 watts per L91, Turbo isn't going happen with lithium primaries. Eneloops would work.

1) Why not just get a TK41 which is the exact same light but it uses 8 AA batteries (if you want to use AA cells)?

2) When you use multiple AA cells in a D size carrier, the cells are in parallel so the voltage is the same as 1 cell but the amperage is divided across all the cells in the carrier.

3) Good luck using only 3 AA cells to power that light. I can't see physically how that would work without a carrier. As stated above, there is no way you will get turbo (or most likely even high mode) with only 3 AA cells. I would highly recommend looking up the max amperage those cells can take if you want to try it.

In HKJ review of TK41, the power consumption was only 3.29 watts for high mode. Granted Fenix rates the TK41 at 335 lumens on, and 350 lumens for the TK60. If there is an electronic difference, even if that pushed the power consumption to 3.5 watts (divided among 3 cells), that is an acceptable power draw for an L91.
http://www.amazon.com/dp/B003EJ1QL6/?tag=cpf0b6-20