Surefire LED's powered by rechargable lithiums

I thought that I would learn from others experiences in running Surefire LED models on R123A lithium ion rechargeables.

Which models can do this?

Any assistance with this question is appreciated.

There have been a number of reports of people using 3.7v RCR123's in single-cell LED SF's, obtaining greater output (and considerably less runtime) with no ill effects, although this usage definitely subjects the drivers & LEDs to higher voltage than they were designed for. I would most definitely not try 2x RCR123 in the two-cell SF's, and have not yet run into anybody on CPF that has been doing this over a substantial period of time - most say that there is a high risk of

For the two-cell LED SF's, a single 1x17670 LiIon would be very safe albeit with something like ~70% of the rated output from 2x CR123. Runtime would be excellent. However, some SF bodies do not have the required inner diameter for 17mm cells, requiring a slight boring of the body tube.

It's a tough situation - I run LiIon rechargeables in many of my SF's (using aftermarket LED drop-ins in the 6P / G3 / C3 for example), but my LED SF's (L1, L2) are all on backup duty with 1x or 2x CR123.

Another option besides the standard 3.7v LiIon RCR123 are the various 3.0v rechargeable cells that are available, but all of them are rather poor solutions. I'd highly recommending Mdocod's two LiIon rechargeable guides for more info. I don't have the link handy and recommend using the 'search' function.

Edit: Here's the links. Pretty much the bible when it comes to LiIon rechargeables:
https://www.candlepowerforums.com/threads/161536
https://www.candlepowerforums.com/threads/201375

I've run RCR123s in my L1 Cree for short periods but get edgy about it long term.

I do run my KX2 dual mode head on a single cell body with an RCR123 with good results and no risk of frying the driver - I top off the cells so I haven't done a runtime test (IIRC someone did and got 40 minutes or so on high). And I don't notice much if any drop in output - I'm sure it is lower but it is not glaringly apparent.

The KX1 head does not function with an RCR123.

All of this assumes 3.7v (4.2 off the charger) cells and not the 3v rechargeables which are an option of course.