He should use L91s if eneloops don't cut it they make cost an extra dollar or two but could save him $50 in the long tun.Other pair of Xtar AA Li-ion's went through son's X-Box controller. I'm saying it lasted quite a long time but do not have any hard numbers to compare with alkaline. The boy found some alkies for replacement. He does not like the sudden drop when the Li-ions are depleted. One can only hope his $60 controller does not get poisoned with battery bile.