So, I’ve never known this was possible, or at least, advisable, for most lights…
But a flashaholic friend of mine is telling me he runs 2x CR123 primaries in all his 18650 lights.
I thought there were a handful of lights out there that you could do this with, but will it really work for the majority of them?
I love my 18650 lights, but it’d be great if I could use CR123s in them some times.
Or more specifically, does anybody know if this will work in a Convoy C8, with an XML2?
This might work with some lights. But depending on the light it might damage the LED or the driver.
Personally, I’d never do this. Not so much out of fear of damaging the light, but rather because of the risk of battery explosion.
Running lithium cells in series is very risky. There have been multiple stories of lights exploding when used this way. The danger is when one cell runs down faster than the other cell. The empty cell then gets reverse-charged. This causes it to very rapidly emit a large amount of heat and oxygen. When this happens in an enclosed metal flashlight battery it can explode.
I’ve heard far fewer stories of single-cell lithium batteries exploding. I consider them much less risky, though care must be taken with ANY lithium cell.
Yes, you can use it but there will be no light soon.
Give you an excuse to go and buy another one or mod it with another driver….
Cheers
6v with alkalines or eneloops will work with the nanjg driver
but 6v with cr123 will heat up the driver very quickly.
it works without burning things but efficiency will drop if you measure with a meter
This has been discussed in detail in a few threads.
Search yields- Nanjg 105C (and variants) on 2 x CR123 cells (6V Nominal)
Assuming it’s a stock Convoy, then no. The driver in it is rated to 4.2v, i.e. 1 x Li-ion.
There are lights that use drivers that support a wider voltage range and will allow even up to 2 x Li-ion (8.4v).
But as the norm, most 18650 lights will not work without damage on more than 4.2v
Ask him for a list of all his 18650 lights.
I’m betting it’s a short list.
Depend on your friend’s flashlight. Some 18650 flashlights also available for 2xRCR123 (with driver can accommodate up to 8.4V), but your stock Convoy can not.
A buddy and I just last week swapped in the stock convoy s6 pill/driver/led into a 3x AAA headlamp. We got it installed fairly easily with mode switching hi/med/low like it was stock, put it all together, the stock cover fit just perfect....
he he used it for a couple hours and at the end of the night he swapped in 3 fresh AAA batteries, turned it on to make sure it worked, ...... it did, for about 2 seconds LOL, fried the emitter. 3x AAA=4.8 volts! The batteries he had in at first were low on juices, measuring 3.6V, new batteries killed the emitter in short order. :(
i bought the pill/driver off of him for $5 and ordered a $7 xml2-u3-1a on a noctigon pcb from MTNelectronics lol. It will end up in my new convoy m1 host I just got in the mail today after I add several 7135*380mA drivers and upgrade the wiring/springs.
You can do it. Read the thread I posted above.
That voltage should not have killed the emitter. Remember, the emitter should only get the voltage needed to push whatever current the driver is setup for. 8x350 7135’s would have been fine.
Likely something else happened there.
I’m the flashaholic friend of Kirbot’s, so I feel that I should respond to his thread.
Here’s a list:
Solarforce L2P with Solarforce LC-XML2 single mode dropin, used with either 2 CR123s or a 18650
Solarforce P1D with Solarforce LC-XML2 single mode dropin, used with either 2 CR123s or a 18650
Solarforce L2 with Solarforce LC-XML2 single mode dropin, used with either 2 CR123s or a 18650
Solarforce L2N with Malkoff M61N, used with either 2 CR123s or a 18650
Solarforce L2N with cheap 350 lumen single mode dropin, used with either 2 CR123s or a 18650
That’s all I can remember off the top of my head. I have about a dozen more coming.
Running lithium primaries is not a risky venture at all. I have been using various Inovas, Surefires, and Streamlights with CR123s for a decade with zero issues. I can list those as well if so desired.
There are multiple stories of car batteries exploding as well, frequently with significant force and spewing battery acid all ofther the place. Quite a rare occurance.
I agree that battery explosions are rare. But it’s still safer to use a single cell over 2 cells in series.
If you’re going to use an 18650 light size light anyways, you might as well use the much safer single-cell option.
The only lights I have that use 2 lithium cells in series are my MTG2 lights. I only run them in short bursts and never get anywhere close to letting them go dry. Just holding them makes me nervous when they’re on. I’d use them with a single-cell if I could, but they require 6v so need 2 cells.
There was a story just last week about someone whose flashlight exploded in his mouth. And he was using it with 2xCR123 cells in series.
first I love my Mt-G2 lights. second I have a handy dandy 4 cell $16 external battery bank/charger. what I noticed is that it banances any cells in it.
So I take full cells run them in my light. run them down, charge them, take a new set of charged and baanced (that just means I left the charged cells in the EBB for a while and repeat.
I LIKE to run 2 and 3 cells in series for the MT-G2 emitter and if one avoids “mystery” cells and chineese cells (all mine are lap top pulls) absolutely! no isses or worries.
Think about it every laptop has cells in series, you dont here about them blowing up all the time.
YMMV
First off, I wouldn’t take any of this too seriously.
But looking at that list, you’ve really just named 3 Solarforce drop-ins and two other p60 drop-in’s. That’s not actually a large list and they are all the same product. The p60 being a Surefire thing, which when first introduced was designed for 2xCR123a and 18650’s didn’t even exist. So it is more common to find them with higher voltage support.
Often the biggest issue with supporting higher voltages is, it comes at a trade off. The Solarfoce p60’s are a great example, they suck on an 18650 with poor regulation. But run much better on 2 x li-ion.
The wider voltage range support usually means a compromise and less performance on lower voltage power options.
Logic would suggest, that just because you personally haven’t had an issue, it doesn’t mean it’s safe.
My Olight Baton S20-L2 is designed with 2XCR123 support. I have had CR123’s in it for a while now, and the last time I turned it on, I noticed the voltage indicator LED in the e-switch lights up RED. I think it’s time to get the CR123’s out of there! The reason I’ve used 2XCR123 in this light is because the driver gives me 50lm more with that configuration. I think I’ll just switch back to 18650 and be happy AND safe! Besides, I’m not really into wasting dollars on non-rechargeable Lithium primaries while I have over a dozen 18650’s from laptop pulls just laying around. :bigsmile: