I've never had a problem with any of my M4 batteries. I still have my 2 original M-401 batts ordered over a year ago from AEC, and 3 M-402's (2 auto, 1 manual) that I ordered 3 months ago from sharp-smoker. They all still work, although I always did notice slightly less vapor production from one of the 401 batteries. I just got to the point where the only time I'd use that one was when the other was charging.
Hey Norby, lucky you
I happen to vape at least as much as I used to smoke, maybe more?(2 packs a day)
That being said, I'm charging these batteries twice a day each. It's only been a couple weeks since I got the manuals in and they are working just fine, so far. The stainless one seems to loose charge just a bit sooner than the black one, maybe half hour? Still, thay are both lasting about 3-4 hrs from a full charge.
I wanted to try the stainless because of Papa's trouble with the discoloration issue, no problem so far. I don't really like the mint green LED on mine, harder to see in the sunlight, if blinking.
My auto 402 is still going stronge!(looking for some wood to knock on)
Brady, sorry your having so much trouble, are you using auto batt's only?