You may remember that a few months back I completed a project to extend the runtime of my DiNotte AA lights. I can report success with them. For both my two front lights and my rear light, the doubled battery backs driven by lithium AAs made it easily from sunset to the food station (approximately 50 miles/four hours), with the rears on strobe high/low setting and the fronts on low. They had plenty of life in them but I changed them at the food stop anyway, thinking it was better to do it there than on the roadside. Then the second set of batteries made it the next three-plus hours until daybreak. To be honest, I think they could have gone all night. I supplemented with the DiNotte helmet light on a strobe high/low setting, and it went all night on a single battery pack loaded with lithium AAs, although that light was visibly weakening as dawn approached. Although neither cheap nor without some hassle, it may be the ultimate lighting set-up for the long brevets.