I sent them an email, will report back.
I think it will work on single 3.7V batteries whatever the size.
Their reply stated that it would work with 3.7 V 14500...But I am still wary , not sure why. I mean 3.7 V is 3.7 V no matter what size the battery or what capacity ...right ?
My Email:
Hello
This light can use a single 1 X AA battery(1.5V) or 1 X CR123(3.0V) battery or 1 X RCR123(3.7V).
Can It use a 1 X 14500(3.7V) battery?
Thank you for your time
Their response:
Hello Brian,
Yes, RRT-0 is also compatible with 14500 battery.
Best Regards,
Service Center
SYSMAX Industry Co., Ltd.
Add: Rm1407-08, Glorious Tower, 850 East Dongfeng Road, Guangzhou, Guangdong 510600 China
Tel: +86 20 8386 2000
Fax: +86 20 8388 2723
Web: www.nitecore.com ; www.jet-beam.com
Yes, unless it’s direct-drive when you put a Li-Ion in, but most likely it’s not (otherwise they wouldn’t claim compatibility with 16340 batteries).
With a direct-drive, though, using e.g. IMR cells can cause too high currents and kill the driver (or LED, but that's less likely with XM-L lights).