Surefire Kroma-MS Battery Use Update

I wanted to let current owners and future owners of the SF Kroma light know of some battery tests I've done with the Kroma-MS. The Kroma-MS, and I assume the regular Kroma, can operate normally with either a non-rechargeable CR123A pair of batteries or with the rechargeable RCR123A pair of batteries. The barrel of the Kroma body is not large enough to handle the popular 18650 rechargeable battery. The Kroma body is capable of fitting the rechargeable 17670 battery, but the operation of the Kroma is affected by this battery. Straight from the charger, the 17670 Sony Energytec battery reads 100% charge and 3.61 VDC under load on the Ansmann Energy-Check LCD battery tester. The ZTS MBT-MIL tester shows 100%, but does not display the load voltage. The Kroma-MS will operate the white LED under low power and high power mode normally, but when you switch to the other colored LEDs, i.e blue, red, IR, or yellow-green, the selected colored LEDs light up as well as the main white LED. This occurred in all switch positions for all the colors. This could be a potentially hazardous occurance, when you need to have only a covert red, IR or yellow-green LED lit.

I don't think this is a defect with the Kroma in any way, but rather something to do with the regulation circuit in the light. As a reference, two Energizer CR123A batteries stacked and measured on the Ansmann at the same time gave a reading of 100% and 4.99 VDC. I felt it was important to let all Kroma users know this, as in a tactical environment it may be important. Thanks, and stay safe!

First up, thanks for the information,

Is the output on High/White affected at all by use of the 17670 vs. the primary 123s?

MSax

MSax,


I didn't notice any visible difference between regular lithium batteries, rechargeable RCR123A batteries or the 17670 battery. I only have a Luxmeter, but will see if there is a measureable difference. I don't think it damaged the light using the 17670, but it sure doesn't act the same as with the regular CR123 batteries or the rechargeable RCR123 batteries. I was suprised to see the difference in the way the LEDs acted. I might try to run down the 17670 and try it again. Thanks,

Great info for the people on the Kroma passaround too - thanks Greg!

Hi there Greg nice to hear from you...glad you are safe!!

Why do you think the Kroma activates de other lights...do you think the combined voltage of the two unprotected RCR´s may have damaged the circuit or is this condition not present when you switch back to those batteries..in other words, is this condition atributable only to the 17760?

LED61,

Thanks for the well wishes. I've got a short reprieve until I go back to Iraq in November. As for the Kroma, switching back to the regular lithium batteries or the RCR123A batteries puts everything back to normal. There appears to be no damage done by using the 17670 battery; it only causes the wierd extra white LED to come on when selecting the colored LEDs. My main concern is for anyone relying on the covert operations of the IR LEDs. Using the 17670 battery would cause the IR LEDs AND the white LED to come on at the same time. I think there is more than meets the eye with the new Kroma flashlight. The electronics in the head do react differently than other lights.

Thanks for the review/insight Greg. I run primary cells in all my flashlights and am hesitant to run protected RCRs through my Kroma with the possibility of frying something inside..Stan

I believe Greg uses unprotected RCR´s is that right Greg? I think the protected RCR´s are too fat but maybe you can clarify this Greg? One more thing, how do you tell when not to run down the unprotected cells if these are the ones you use?

I also want to toss this tidbit out to everyone on rechargeable batteries for the Kroma. I have four (4) Pila 600S cells and only two (2) fits the SureFire Kroma. When using these rechargeable batteries, I do not notice a difference in performance between the primary cells.

how much do these batts cost? can they be used in the a2?

LED61 said:

I believe Greg uses unprotected RCR´s is that right Greg? I think the protected RCR´s are too fat but maybe you can clarify this Greg? One more thing, how do you tell when not to run down the unprotected cells if these are the ones you use?

Click to expand...

I do use unprotected RCRs, as well as regular lithium batteries with no ill effect. The specific unprotected RCRs I use are the ones that shipped with the Peak CPF Special 2005 last year. I tend to not run the RCRs down too much before putting them back on the charger. Better safe than drained and dead, hehe.

RadarGreg said:

I wanted to let current owners and future owners of the SF Kroma light know of some battery tests I've done with the Kroma-MS. The Kroma-MS, and I assume the regular Kroma, can operate normally with either a non-rechargeable CR123A pair of batteries or with the rechargeable RCR123A pair of batteries...

The Kroma-MS will operate the white LED under low power and high power mode normally, but when you switch to the other colored LEDs, i.e blue, red, IR, or yellow-green, the selected colored LEDs light up as well as the main white LED. This occurred in all switch positions for all the colors...

Click to expand...

I have the RD/BL Kroma and put on an A14, put in a SF B65 (tight squeeze) and it did the same thing. Switched back to SF123's and back to normal.

Odd...

I have used the A14/AN14 and B65 combo on P60's, KL3's old and new, and KL5 with no problems.

Redd

I swapped my U2 body to the regular Kroma and all functions work fine with AW 18650 protected cells. Output looks the same as primaries.

Can anyone else confirm that it is safe to use the Kroma with 2xR123s?

That would be a really great combination.

Thanks for the heads up guys!

MSax

I can Conf. that. I tried using 2 x RCR123 3.0V Protected cells and it worked perfectly, no problems with function at all. The only difference I can see is that the tailcap becomes a bit tighter to push because of the cells being slightly longer.

Ken

Are those Tenergy's? could someone confirm that it is ok to run 2 rcr123a's 3.6 v.?

RadarGreg etal,

I am doing a review on the K2 KROMA right behind "curse" in the "Reviews" section, "Surefire K2 KROMA & KROMA Milspec", Post #40. One of the things that I have reported is that the U2 body is dimensionally interchangable with the K2 body. Therefore if you have a "wide-open" U2 (gen. 1) body, almost any battery is now available to the K2 (or by inference, the K2MS also). Your news on just what the K2MS will tolerate is interesting.

I, too, am beginning to pick up evidence that the regulation circuit of the K2/K2MS is very sensitive to what powers it. There are apparently, inefficiencies &/or limitations in the head that make it very particular. I do not have the expertise to understand just what these peculiarities are, just that they are present. My runtimes are not as long as I expected from a light with this power output. I also accidentally discovered that the light will not go to "High-White" in any switch position if you have a bad, low-voltage battery in the mix.

So, even though, you may be able to "power" the light with a wide variety of batteries, by switching out the K2 body with a early U2, the head may not tolerate it. Be careful fellas. I'm not qualified to comment further.

Hope this helps,
Flashdark sends.

Even if one of us was willing to sacrifice our light to see what sort of battery could power it, the battery might do just fine initially only to find a year from now that something bad has happenned to the LED head or the circuit and the light's life has been severely shortened.

RadarGreg, check the mA's at the tailcap area with a DMM. If the mA reading is higher or the same with two RCR123's, compared to two CR123A's then you are over driving the circuit. If the current (mA's) is considerably lower than a reading with two CR123A's, then you are ok, and the circuit is regulating correctly. We flashaholics need a DMM when expirimenting with different cell types in our flashlights.

Bill

Bullzeyebill said:

RadarGreg, check the mA's at the tailcap area with a DMM. If the mA reading is higher or the same with two RCR123's, compared to two CR123A's then you are over driving the circuit. If the current (mA's) is considerably lower than a reading with two CR123A's, then you are ok, and the circuit is regulating correctly. We flashaholics need a DMM when expirimenting with different cell types in our flashlights.

Bill

Click to expand...

Hi Bill. I tried doing some current measurements this summer with the Kroma-MS and didn't have much luck. Using a Fluke 189 DMM to check the current flow, it would only read it in the low power mode for the white LED. I could not get it to light up in high power mode. The colored LEDs pulled about 100 mA if I remember. I tried the measurements using both Panasonic CR123A batteries and with rechargeable RCR123A cells. Both types of cells gave me the same readings.

I'm still a bit confused on how to get the Kroma-MS to turn on in high power mode using the multimeter. Using a paperclip or other shorting object, it would come on it high, but not with the multimeter. I verified the internal resistance of the meter was around one ohm, which is normal. The Kroma tailswitch has two resistances, 10 ohms for low power and zero ohms for high power. Anyone else who has tried the current measurements, please add to the thread. Thanks!