Author Topic: Batteries question  (Read 445 times)

Offline JoW

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Batteries question
« on: September 26, 2019, 01:12:12 pm »
Can anyone help me with a batteries question?

I have a fenix HL55, which will run off a single 18650 or two CR123A batteries. However it doesn't seem to be able to run off two rechargeable 16340 batteries (the rechargeable version of the CR123A) can anyone explain to be why this is the case? I don't think it's the voltage as if it can support the CR123A it should support the 16340 so I'm baffled...

Offline Benfool

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Re: Batteries question
« Reply #1 on: September 26, 2019, 03:13:02 pm »
Hey Jo

Think it probably is a voltage issue....

18650 cells are Li-ion, so voltage when fully charged is ~4.2v, similarly, rechargeable 16340s are also ~4.2v. By putting 2 16340s together on top of each other, you are connecting them in series, ie adding the voltages. Therefore, by using Li-ion 16340s, you are putting double the voltage through the light that the electronics are designed for.

On the other hand, CR123A batteries are Alkaline and have a max voltage of about 3v. Again putting two of these end on end will give a max voltage of 6v. My guess is that the circuitry in the light is designed for anything up to 6v, but anything above it cuts off.

So my advice would be either stick with 18650s (which are cheap and easily available), or use CR123A if you want a non-rechargeable alternative.

Hope that makes sense!

B

Offline andrewmc

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Re: Batteries question
« Reply #2 on: September 27, 2019, 02:07:08 pm »
On the other hand, CR123A batteries are Alkaline and have a max voltage of about 3v.

pedantic note - CR123As are primary lithium cells (Li-MnO2), not alkaline (Zn-MnO2). Otherwise I agree with everything you said.

Offline Benfool

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Re: Batteries question
« Reply #3 on: September 27, 2019, 02:33:40 pm »
I stand corrected! Serves me right for guessing and not looking it up!

B