Well, I hadn't thought much about this subject until today. I just received a single "AW IMR 18650 2000mAh 3.7v battery" from a seller (r-Isales) in Ebay. Everything was fine until I put it into the charger next to my other AW IMR 18650 2000mAh 3.7v battery. This is what I saw: Now one of these is not like the other. Can you tell? Im not sure if this is an actual issue yet, mind you. The new battery is still charging. Maybe something changed in terms of packaging or manufacturing? Its been known to happen. Then again, counterfeit batteries have also been known to pop up, and AW is one of the ones that have had a past with this specific issue (from what I gathered from my Googles anyway). Oh and then there's this: In any case, I'm wondering if anyone has some insight/input here? @CentiZen @BLAZING OG @OF @Pipes ? Also, let this serve as an FYI for everyone else. This is something I hadn't considered when I purchased this unit. edit: Just an afterthought... I was going to stack these in my Persei with the long tube SS kit. Is that a bad idea to even try at this point?