Actively Charging Battery (for battery slice)

[theNewEasy]

I'm using an x220 with battery slice attachment. (Two batteries.) One battery dis/charges at a time while the other is inactive. I was wondering if there's a way I can change which one is active without having to wait for it to fully dis/charge. After reading up on lith-ion batteries I've become scared to have one sitting at full charge for too long. It's my understanding that you can't have two active at a time, so ideally the active battery would alternate every ten (or so) percent of dis/charging, keeping them consistent with each other.

edit: OS: win7

[bill bolton]

I was wondering if there's a way I can change which one is active without having to wait for it to fully dis/charge

No, there isn't.

Cheers,

Bill B.