Hi guys, I've been vaping for about a year now and never really had any issues. During the last month or so my M401 batteries started dying for no reason. The symptoms on all of them are the same, when I charge them the light blinks, but when i try to drag on them, they do nothing. It seems that the mechanism who activates the battery stopped working. I don't know what it is, a bad batch from the factory (one of the original batts is still working) or my fault? I have 5 batteries just laying on my desk collecting dust, is there a trick to fix them? Thanks.