Fenix TK40 battery question

TwinBlade · Sep 13, 2010

Ok, another noob question,

If I use NiMH batteries at 1.2v vs Alkaline at 1.5v, is the out put still the same? This sucker takes 8 of them, so I would be missing 2.4v of power with rechargeable's.

Also, does anyone know how much run time I will lose going with rechargeable's vs alkaline? Say, 2500 mah NiMH...

I really like this TK40. I am considering it for purchase.

TIA.:thumbsup:

HKJ · Sep 13, 2010

The light has stabilized output, i.e. it keep the same brightness with both types of batteries, only reducing brightness when the batteries are close to empty. On turbo you will get longer runtime on NiMH batteries, than alkaline (Alkaline can not really handle the high load).

Duglum · Sep 13, 2010

If you own 18650 Li-Ion Batteries you may consider the TK30. It's like the TK40, but powered by 2x 18650 instead of 8xAA.

Steve'O · Sep 13, 2010

TK40 will also run happy on 4 nmh batteries on turbo, and to my eyes looks just as bright.

It = less run time, but also less weight too.

TwinBlade · Sep 13, 2010

Thanks for all of your input guys. I appreciate it..

I like the look of the TK40 over the 30, and I have gobs of Duracell and Energizer 2300-2500 mah batteries from all of my R/C racing I used to do. With all the remotes I ran, I had to go to rechargeables from a cost standpoint. It makes sense to use them IMO.:thumbsup::thumbsup::thumbsup:

Swedpat · Sep 13, 2010

Duglum said:
If you own 18650 Li-Ion Batteries you may consider the TK30. It's like the TK40, but powered by 2x 18650 instead of 8xAA.

You forgot TK30 also runs on 1x18650, 2xCR123 or 4xCR123...

Chicago X · Sep 13, 2010

TwinBlade said:
........If I use NiMH batteries at 1.2v vs Alkaline at 1.5v, is the out put still the same? This sucker takes 8 of them, so I would be missing 2.4v of power with rechargeable's.........

As Steve'O mentioned, the light can run on 4 batteries. It is wired up in two parallel series of four cells, so you are only "down" 1.2 volts.

The higher discharge rate (and lower internal resistance) of the NiMH cells makes for a better choice than higher-voltage alkaline primaries in this application.

Good luck with your purchase ! :thumbsup:

Fenix TK40 battery question

TwinBlade

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HKJ

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Steve'O

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TwinBlade

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Chicago X

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