jj - a word of warning if you are going to be using an adapter. I have a "XPOWER 900 " which i find to be superb. It is an ego clone. Anyways ....it has a 301 attomiser and i bought a 301 to 510 adapter to give me access to all the 510 goodies. Worked fine. Then when the battery ran out as it normally does after a day and a half i went to charge it and........nothing. The charger just went green light. Same thing happened to my next battery too. My wife has the same kit as me and her first battery went the same way. We thought they were dead.
I posted my problem on an English forum that i also use and hey presto a guy advised me that i may have tightened the adapter down too tightly and moved the small disc, with the hole in the middle, down in to the battery to far for it to touch the charger connection when i tried to recharge it. I used a small piece of wire to pull that disc up a little (talking about 1 or 2mm). Connected to the charger and YESSSSS the red light came on the battery blinked 3 times and began to recharge.
So anyone out there reading this that thinks their battery may be dead. Think about it. You may have screwed your atty on so tight that it moved the disc with hole in. Or screwed your adapter on so tight that it did the same.
I am no expert on this. This is just what happened to me. It could happen to you too. I have 4
batteries working again that i thought i'd killed.
I ordered two more batts. And two Ego kits before i fixed my batteries. So it looks like i'm gonna have plenty of spares....lol