Review on 2-Pack SNSYIY 3.7V 3600MAh USB Rechargeable Button Top Batteries For Klarus Flashlight (XT11X, XT11GT, XT30R.) by Ashutosh Takumatla

I didn't notice at first, but when using these batteries in my ThruNite headlamp, the light would flicker and shortly thereafter shut off. Turning the light back on the light would stay on for three to five seconds and shut off.At first I thought the battery may have been low, but I didn't recall much burn time on that charge, perhaps 5 or 10 minutes NOT on the brightest setting but put the battery back on the charger. I cycled through the two batteries plus the OEM battery that came with the ThruNite headlamp, but after a few weeks determined the issue was happening with one specific battery.So, one of two batteries in this set is bad and perhaps had a half dozen uses.Don't know how long the remaining battery will last.Charging batteries in Nitecore UMS4 Intelligent USB Four Slot Quick Battery Charger for Li-Ion/Ni-MH/Ni-Cd/IMR 16340 14500 18650 21700 20700 AA AAA.