Patent ID: 8314594

Claim:
A system, comprising: an implantable medical device having a rechargeable power source having a recharge interval until a time when recharge of said rechargeable power source is desired, said rechargeable power source having a voltage, a total charge capacity which changes over time and a charge level; electronic componentry, operatively coupled to said implantable medical device, configured to: record a cycle age by counting a number of recharges of said rechargeable power source indicative of a number of times said rechargeable power source has been recharged; record a chronological age of said rechargeable power source; determine said total charge capacity of said rechargeable power source at a first time by subtracting a charge capacity based, at least in part, on said cycle age of said rechargeable power source and a charge capacity based, at least in part, on said chronological age of said rechargeable power source from said total charge capacity at a second time, said second time being earlier than said first time; measure a voltage of said rechargeable power source; determine a state of charge as a function of said voltage; determine a charge level of said rechargeable power source as a function of said total charge capacity at said first time and said state of charge; and determine said recharge interval as a function of said charge level and a programmed rate; and a user output, operatively coupled to said electrical componentry, configured to communicate said recharge interval to said user.