Two well known issues with Surefires - they have battery compartment diameter issues with some rechargeables , they have problems with the higher voltages found in some rechargables , check voltages with a DMM . I get primaries pretty cheap , and get pretty long service life with them , not sure they are worth the bother . For the cost of cells and a charger , I can buy lots of fresh primaries for the cost of the setup .
In some applications , I find headlamps indispenceable .
Chris