Okay, I'm new to the voltage/amp biz. Here's the issue. I just got a Solarforce L2m, which can be shortened to accept a single CR123. I don't have any rechargeables that size, so thought I'd buy a primary and check it out. Now... which drop-in should I install? I have two:
a) Manafont Ultrafire XM-L 3-mode (the famous one)
b) Supasizefries XM-L T6, with a 3 Speed Shiningbeam Driver (Low/Med/High), 2.8 amps on High, 2.8-6 volt input range. Described here: http://bit.ly/AvibuL
So, what to do? Would either work? And down the road I'm going to buy some Li Ion batteries in this size -- which drop-in would work best with those?
I don’t think these drop ins will work with a primary. At least not bright and not for long. I use a Solarforce 1-4.2v drop in in my 2xAa body and it gives a very bright light out. I guess this kind of low voltage ones will be better for single primary lights.
The MF UF will not work with a primary cr123. Solarforce makes some low voltage drop ins that should work. Look for the ones that say 0.8v - 4.2v voltage range.
I'll second this recommendation. I have a L2m running single cr123 primary and it seems to run fine with a Solarforce 280 lumen, 0.8-4.2v, 3-mode, XR-E drop in. Here is the link to their current offerings in that voltage window. I'll just add that I'm pretty new to the drop in game and some of the other, more sage members here might have better advice.
Right. I got the Solarforce low voltage 3-mode XM-L drop-in:
I'm firing it up with a CR123 primary at the moment, as I don't have a li ion in that size. It's really dim. At high it's perhaps the same brightness as the Manafont 3-mode XM-L on medium (with 1x18650). Definitely not a flawed drop-in -- when I power it up with an 18650, it's super-bright.
Is this just how single CR123 cells tend to perform? Will it be any better with the RCR123 I have on order?
Could it be this drop-in's required voltage is still not low enough? It's 3.7 volt. I guess a primary is only 3 volts. In fact, an RCR123 is nominally 3.6 -- is that going to be an issue?
Your link is to a drop-in that requires 3.7 volts and a cr123 primary is 3 volts, so there just isn't enough juice available for that particular drop-in. I have a L2m with this SF 3-mode and it works fine; http://www.solarforce-sales.com/product_detail.php?t=RB&s=10&id=298 Of course, it isn't an XM-L, but plenty bright nonetheless.
Right. So does this mean an RCR123 is also going to fall short? Or is the difference between 3.6v and 3.7v less crucial? (I think the li ion spends at least some time at a higher stage of charge, no?)
Your link clearly states that the drop-in is to be "Powered by: 18650 3.7v x 1". So I'm assuming that an 18650 is the only way to go. I'm sure someone much better informed will chime in soon to clarify this because I probably don't yet know enough to be giving advice.
You'll need lMR cells if you plan to use this dropin in a single rcr123 light. High current draw might cause a vent off of your regular lithium ion cells.
Yes. The RCR123 will squeeze out 4.2 volts freshly charged, but will quickly diminish and the voltage will sag. I gave up on that configuration. It will initially be bright as the voltage will equal what is ideal for the light. For serious use, I wouldn't count on this. The lower operating current, the better, but just don't exceed the voltage maximum with any drop-in. Honestly, I've yet to find a stable RCR!23 that I could count on.
Thanks all. Especially good to have the warning about li ions. (That's of course not a concern with 18650s, right?) So, do I buy some IMRs, or do I just buy a lower-voltage drop-in, and throw this one in a full-sized Solarforce?
That looks as if it's the one I should have bought. Although my new determination is to buy nothing but a) XM-L and b) neutral or warm emitters. (I may have to lean on you for a custom drop-in after all.)
Okay, just wanted to understand the theory here. Is the concern that a 3.7v drop-in is likely to discharge an RCR123 too deeply, causing it to vent? Or is the difference between 3.7v and 3.6v somehow crucial here?