DBS V3 XM-L battery question

Hello all, first post!

I have a Dereelight DBS xm-l that I am wanting to keep as compact as possible. It has the 3sm pill. I have the 18650 extender which is way too big for pocket carry. The output on 2 rcr123 is great but I know I'm toasting my cells and playing with fire. I don't think the 18500 extender would be too awfully big but I'm not positive.

Would IMR 16340 be my best bet? They can handle the high draw and the DBS has voltage cutoff protection correct? I could use 18500 with extender if I must. Would lifepo4 18500 work at all or be less bright?

The voltage indicates it should be able to be used with one 18650. Would that work but with reduced brightness? What about an IMR 18650?

Thanks for any help :help:

Dajabec,

I recentlly purchased a bunch of Deerelight stuff (small/DBS/Aspheric heads, various extenders, a whole bunch of pills, smooth and OP refectors). In this mix I have two XM-L pills.

One pill is the Deerelight XM-L that you own. Running on only one 18650 it is only about half as bright as using two. I don't think switching to an IMR cell will help you because the issue is voltage not amps.

I also have a XM-L pill that I purchased from Nailbender. This pill is specifically designed to work with one battery (it cannot be used with two) and is approximately the same brightness as using two batteries with the Deerelight pill. Using one battery (of course) reduces the run time by about a half.

I really like the Nailbender solution. It creates the same brightness using only one battery. Since you can get 18650 batteries that are 2900 MAH, seems to be a better solution that using two 18650 (which are 1500 MAH each), plus it requires no extender. Also with the Nailbender solution, you have a choice of color (I prefer the warmer 4500K color to the cool white). The warmer color is slightly less efficient (T5 vs T6 bin) but the slightly lower output is worth the tradeoff for me. Also I like the 3 level spacing better (5%,30%,100% vs 25%,50%,100% on the Deerelight pill).

Andy

Andy, you are missing one point though. The higher the voltage, the lower the amp draw, so even though 1 18650 may have 2900 mah, it is only half the voltage of 2 18500s at 1500 mah. I know the math isn't exactly linear (I know 2 18500s wont give you the equivalent of 3000 Mah) but 1500 mah goes a lot further when its at 8.4 volts vs 4.2. If form over function is the goal, 2 18350 IMRs will work in the DBS just fine, but will have reduced runtime (Jay aka Flashcrazy estimated 2 IMRs at about 20 min on high) 2 18500 will give you descent runtime, albeit not quite as long as the single 18650 in a Nailbender (although I believe Nailbenders single cell pill is DD and the DBS is fully regulated at 2.5 amps) I think it's easier to get good regulation with higher voltage. Many single cell lights are only regulated for a while, then fall into DD when the voltage drops below a point. Not totally sure about the Nailbender though. I have had good luck with Dave, so maybe send him a PM to get more info on his pill (they thread right into the Dereelight reflectors). Good luck and welcome to CPF!

I did take into consideration the higher voltage. So with rough calculations two 18500 (8.4 x 1500) have about 12.6 watt/hours while one 18650 (4.2 x 2900) have about 12.2 watt/hours. I like the smaller length and having to deal with only one battery. The overall capacity seems to be similar. My understanding is that nailbender's pill is regulated at 2.8 amps (not direct drive). Not sure about your observation about getting better regulation at higher voltage (probably true). In comparing my nailbender one battery and deerelight two battery pills, the deerelight is a bit brighter and consumes a bit more more (both are around 11 watts). Some of this difference is due to the cool white T6 deerelight vs 4500k T5 nailbender.

Great stuff guys, just what I was looking for. I didn't even think about 18350 IMRs. I don't use the light a whole lot or on high all the time so they should last me long enough. If I have to charge more than I'd like I'll look into the Nailbender option, thanks for bringing that to my attention.

BTW why is it in the review of the Thrunite Scorpion 2 you can use 2XCR123a batteries but not 2 RCR123? The DBS explicitly forbids CR123 because they can't handle the voltage, and warns RCR may not be able to handle it or have shortened lifespan. If the reasons for both limitations is current draw, why are primaries better than RCR in the Scorpion and RCR better than primaries in the DBS?

Dajabec,

CR123a batteries have lower voltage than RCR123s. CR123 are nominally 3.0 volts while RCR123 are 3.7 (fully charged voltage is 4.2).

dajabec said:

Great stuff guys, just what I was looking for. I didn't even think about 18350 IMRs. I don't use the light a whole lot or on high all the time so they should last me long enough. If I have to charge more than I'd like I'll look into the Nailbender option, thanks for bringing that to my attention.

BTW why is it in the review of the Thrunite Scorpion 2 you can use 2XCR123a batteries but not 2 RCR123? The DBS explicitly forbids CR123 because they can't handle the voltage, and warns RCR may not be able to handle it or have shortened lifespan. If the reasons for both limitations is current draw, why are primaries better than RCR in the Scorpion and RCR better than primaries in the DBS?

Click to expand...

I am currently using two 18350's in my Deerelight XML V3, and it works perfectly.

dajabec said:

Great stuff guys, just what I was looking for. I didn't even think about 18350 IMRs. I don't use the light a whole lot or on high all the time so they should last me long enough. If I have to charge more than I'd like I'll look into the Nailbender option, thanks for bringing that to my attention.

BTW why is it in the review of the Thrunite Scorpion 2 you can use 2XCR123a batteries but not 2 RCR123? The DBS explicitly forbids CR123 because they can't handle the voltage, and warns RCR may not be able to handle it or have shortened lifespan. If the reasons for both limitations is current draw, why are primaries better than RCR in the Scorpion and RCR better than primaries in the DBS?

Click to expand...

Not exactly sure, but I believe it has to do with the capacity vs ability to discharge. Not sure why 123s are OK in a Scorpion but not RCRs. Maybe the RCR can, but not over its life of numerous recharge cycles and 123 primaries only have to last once.

Also, good call Andy on the Nailbender. Dave must have gotten some better boards for the big guns because when he made my last dropin he only had 2.5 amp and DD available (and the 2.5 would drop out of regulation when voltage dropped, to what I can't remember though)...Now I may have to have him make me one too...:sigh:

bkumanski said:

Not exactly sure, but I believe it has to do with the capacity vs ability to discharge. Not sure why 123s are OK in a Scorpion but not RCRs. Maybe the RCR can, but not over its life of numerous recharge cycles and 123 primaries only have to last once.

Also, good call Andy on the Nailbender. Dave must have gotten some better boards for the big guns because when he made my last dropin he only had 2.5 amp and DD available (and the 2.5 would drop out of regulation when voltage dropped, to what I can't remember though)...Now I may have to have him make me one too...:sigh:

Click to expand...

123 primaries would only have to last once in the DBS as well, yet they seem to be warned against more strongly than the RCR while they are supported on the Scorpion.

Great topic!!
I recently purchased a DBS XM-L, I was tempted to get a lower voltage pill such as a Nailbender so I could use 1 x 18650, however won't this increase the amperage through the tailcap switch to a higher level than what its rated to?

cheers,

dajabec said:

Hello all, first post!

I have a Dereelight DBS xm-l that I am wanting to keep as compact as possible. It has the 3sm pill. I have the 18650 extender which is way too big for pocket carry. The output on 2 rcr123 is great but I know I'm toasting my cells and playing with fire. I don't think the 18500 extender would be too awfully big but I'm not positive.

Would IMR 16340 be my best bet? They can handle the high draw and the DBS has voltage cutoff protection correct? I could use 18500 with extender if I must. Would lifepo4 18500 work at all or be less bright?

The voltage indicates it should be able to be used with one 18650. Would that work but with reduced brightness? What about an IMR 18650?

Thanks for any help :help:

Click to expand...

+

I use 2X18500 {unprotected AW 18500s' & magnetic spacer}
for my DBS V3 w/ 3SM XM-L ,..smooth reflector

Truly one of my favorite lights, not too big & great beam

:thumbsup::thumbsup::thumbsup::thumbsup::thumbsup:

...a single 18650 wont give you enough juice to power the XM-L properly,..you need at least 2 Li-ions
(don't be afraid of unprotected cells or IMR, they allow best flow of current)
2x18350 or 2x18500 or 2x18650

hope that helps

lightforce2 said:

Great topic!!
I recently purchased a DBS XM-L, I was tempted to get a lower voltage pill such as a Nailbender so I could use 1 x 18650, however won't this increase the amperage through the tailcap switch to a higher level than what its rated to?

cheers,

Click to expand...

I currently have a DBS running the 2.8 amp XM-L. Not sure what the switch rating is, but so far no problems.

Andy

I just recieved my DBS and upon reading the User Manual , I was suprised they have tick - One constant output and used on 18650 !!type . When I maked my purchased I have ticked 700 lumens !! I guessed they have send me a wrong type Can anyone here advise whether I cam used CR 123? - Thanks