Problem with Nitecore SRT7

[Jdubs]

My SRT7 was working great last night with 2xRCR123s but today the light will barely turn on. The cells are just above 4.0 volts each. Swapping in an 18650, the light works great. Putting the RCR123s in my Klarus XT11 works great. Putting the same RCRs back into the SRT7 and the problems reappear. The symptoms: the light will turn on for a half second and then turn off. Subsequent clicks of the tailswitch have no effect. A few seconds of rest and I might get another flash of light. Sometimes, the light will come on and gradually dim until off, over a 2 second period.

The SRT7 manual specifically allows for the use of RCR123 batteries. I am using Nitecore brand RCR123s. Any idea what's going on when using the RCRs?

 

[HotWire]

I use the 18650 batteries in my SRT7. No problems at all. I put 2 Eagletac RCR123 batteries in and it worked fine. I'm thinking that your batteries are either not fully charged or that the circuit protection is cutting out. The SRT7 is driven pretty hard.... Nitecore batteries have the small button and should work with your "Revenger." Try charging them and/or using AW or Eagletac RCR123 batteries. Good luck!

 

[y260]

If I recall correctly the manual does not recommend using RCR123's. It just states that the SRT7 is capable of accepting them.

 

[Jdubs]

I'm charging the RCRs now, and will test them out again in a bit. I'm not familiar with how protection circuits work. Just before taking the RCRs out to charge them, the light would turn on in high mode, and seem to stay there just fine, and I could click the tailswitch to turn the light off and on repeatedly in high mode, but if I move the control ring in either direction, to either dim the beam or into strobe mode, the flashlight will grind to a halt. Wouldn't you think that strobe or a dimmer beam would draw less current and therefore be less likely to trip a protection circuit? I'm confused.

I don't have any other brand of RCRs to test, but I like the increase in brightness offered by RCR, so I will order another brand, or try some IMRs. Has anyone tried using 18350 in this light?

Looking at the manual now...under Battery Options, it has "Y (Recommended)" next to CR123 and 18650, and just "Y" next to RCR123. So I read that to mean that RCRs are compatible, but are not ideal for the SRT7. Klarus, for their XT11, says something similar, but I recall a post saying the lack for recommendation for RCRs was due to the loose fit of the batteries in the tube, not for any functional reason.

 

[oKtosiTe]

I'm charging the RCRs now, and will test them out again in a bit. I'm not familiar with how protection circuits work. Just before taking the RCRs out to charge them, the light would turn on in high mode, and seem to stay there just fine, and I could click the tailswitch to turn the light off and on repeatedly in high mode, but if I move the control ring in either direction, to either dim the beam or into strobe mode, the flashlight will grind to a halt. Wouldn't you think that strobe or a dimmer beam would draw less current and therefore be less likely to trip a protection circuit? I'm confused.

I don't have any other brand of RCRs to test, but I like the increase in brightness offered by RCR, so I will order another brand, or try some IMRs. Has anyone tried using 18350 in this light?

Looking at the manual now...under Battery Options, it has "Y (Recommended)" next to CR123 and 18650, and just "Y" next to RCR123. So I read that to mean that RCRs are compatible, but are not ideal for the SRT7. Klarus, for their XT11, says something similar, but I recall a post saying the lack for recommendation for RCRs was due to the loose fit of the batteries in the tube, not for any functional reason.

For some lights RCR's (with a max voltage of 2x4.2V=8.4V) fall outside of the acceptable range, where CR123's will output 2x3.0V=6.0V. You're probably aware of this, but I thought it should be mentioned.

 

[candle lamp]

According to the Nitecore website, the RCR123's capacity is about 650mAh.
The current on Max. mode and on Strobe with 1x18650 (2600mAh) at tailcap is about 2.0A and 0.5A respectively in my SRT7.
Therefore the continuous discharge rate on Max. on RCR123As is about 3C (=2000/650). Here, C is the capacity of the cell (650mAh).
I assume that current on 2xRCR123As will be increased more than 1x18650, because the max. output on 2xRCR123As is a bit higher than 1x18650.

In general, the max. recommended continuous discharge of the Li-ion cell (ICR) is 2C. So the above 3C is quite high for RCR123A ICR batteries.
I do think PCB of your RCR123As kicked in to prevent from over-current on time.
I would recommend good quality 1x18650 ICR battery. :)

 

[Jdubs]

Well, my SRT7 kicked the bucket. Only a dim glow from the main beam now, regardless of battery selection. The colored LEDs work fine with either 18650 or the Nitecore RCR batteries.

The symptoms were the same just before it died: perfect functionality with 18650, but only max output was available with RCR123 (no color, no strobe, no dimming available).

Again, all functions worked fine on the RCRs for two days before the problems occurred.

Hopefully, I just got a dud. I like this light and will try to exchange it for a new one.