Just plug it in. However. Although lithium batteries are not supposed to have any charging memory - the older nickel-cadmiums would not recharge fully if not discharged fully - I think it is good practice to discharge your lithium battery fully once every few cycles. The other reality of batteries is that they have a discrete number of charges in them before they die, and they are expensive to replace. So, run on AC when you can. Where's Joe Engel? Cheers, Garrett