Patent ID: 8200444

Claim:
A system comprising: an implantable battery; an implantable medical device powered by the battery, the device having first and second current drain states; and a first resistance connected to the battery through a first current path when the device is in the first current drain state, wherein current is prevented from flowing through the first current path when the device is in the second current drain state; a second resistance connected to the battery through a second current path when the device is in the second current drain state, wherein current is prevented from flowing through the second current path when the device is in the first current drain state; a first memory register configured to store a cumulative first current drain state count indicative of total charge drawn from the battery when the device is in the first current drain state; and a second memory register configured to store a cumulative second current drain state count indicative of a total charge drawn from the battery when the device is in the second current drain state.