TK30 and AW RCR123 question

[blub]

Here is what the manual says for the Fenix TK30:

Uses two CR123A batterys or one 18650 rechargeable battery
Uses four CR123A batterys or two 18650 rechargeable batteries (with extension tube)


Is it going to hurt the AW RCR123 batteries if I use two? I know not to use four but wouldn't two have the same output, but not as long run time as two AW RCR18650 batteries which I've been using? Any reason I shouldn't do this? It sure makes a small bright light in this configuration.

 

[357mag1]

I plan to use two 18350 batteries in mine and see how it works. Right now I'm deployed but my new TK30 will be waiting for me when I get home. I'm not sure how much current the TK30 draws but it could be enough to stress out your 16340 batteries and shorten their life.

I would try it and keep an eye on your battery temperature. As long as they didn't get too hot I would run it in that configuration.

 

[Hack On Wheels]

Two li-ions give you a nominal voltage of 7.4, so assuming the converter runs the emitter near max spec of 2.8A but is also reasonably efficient then we can estimate 1.4 Amps (or less) will be drawn from the batteries. This is in the range of 2C draw from the RCR123s, which isn't unreasonably. I'd still probably recommend some IMR16340s instead though, a bit safer and might run the light a bit brighter.

 

[HKJ]

Two li-ions give you a nominal voltage of 7.4, so assuming the converter runs the emitter near max spec of 2.8A but is also reasonably efficient then we can estimate 1.4 Amps (or less) will be drawn from the batteries. This is in the range of 2C draw from the RCR123s, which isn't unreasonably. I'd still probably recommend some IMR16340s instead though, a bit safer and might run the light a bit brighter.

Not a bad calculation, in my Danish review (Use Google translate to read it) I measured the current:

 

[hoongern]

Keep in mind that the current will go up as the cells drain, so you will be on the edge with the normal protected Li-Co "RCR123" cells.

I would think that AW's cells should be 'ok', but you're definitely going to be shooting > 2C discharge.

My suggestion: Use AW's IMR16340 cells. Much safer, and runtime should be same/longer than 2x LiCo "RCR" cells.

At a 1.5Amp load, the "RCR" cells tend to lose quite a bit of charge, probably to the ~500mAh range (Silverfox's tests show some dropping as low as 255mAh and 318mAh) , which is the same as the IMRs (515mAh)