Having two batteries for the MacBook (or any laptop, for that matter) is a great option to have beyond the obvious travel convenience. For me, if I'm on the living room couch and the power runs down, I don't need to lug it back to the den to recharge it; instead I can swap the batteries and I'm back in business.
But now what do I do with the now depleted battery? Right now I play this battery hot potato game of re-charging and re-re-charging the laptop so that I can always have two fresh batteries.
But that's not an elegant solution.
What I'm looking for is a means to charge a MacBook battery when it is not inserted in the laptop itself.
Is there such a device? I searched the web in vain.