Guys, I bought some exo 21700s this time last year to use on my dovpo topside. Used 2 batteries in rotation, for around 5 months and then moved to my billetbox. This meant my exos got left aside as they were not being used. Ive thrown them in my xtar mc6 charger to charge them up, but no dice. It doesnt seem to want to charge them. I know batteries shouldnt drop below a certain volts, i thought id be fine leaving them aside. What could the issue be? Batteries? Charger? Are the batteries bin fodder now? Or can they be revived?