About a few months ago my Mini Mag stopped working. Instead of putting new batteries in, I took them out and tested the batteries on another flashlight (Inova X2) and it powered up the flashlight. Hmmmm.... it seems that the batteries were ok so there must have been something wrong with the Mini Mag. I called Maglite and they told me the when the batteries get low, the Mini Mag won't work. They told me to put some new batteries in the Mini and low and behold, it's working again. I guess there are plus and minuses to this. Plus, if the batteries are low, it forces you to replace them before they have a chance of leaking. Minus, you have to replace the batteries more often and you don't get full usage of your batteries.