Patent ID: 7786704

Claim:
A battery charging system, comprising: a battery; an electric vehicle, the battery coupled to a propulsion motor configured to propel the electric vehicle; a charging circuit to charge the battery; a charging cost circuit, wherein said charging cost circuit controls operation of said charging circuit; and a timer circuit coupled to said charging cost circuit, wherein said timer circuit provides a plurality of timing signals to said charging cost circuit, said plurality of timing signals corresponding to at least a first time period and a second time period, wherein said second time period follows said first time period, and wherein the charging cost circuit turns on the charging circuit during said first time period in which the charging cost rate is below a first threshold and continues operation of said charging circuit until the battery reaches a first energy stored level, wherein the charging cost circuit terminates the charging circuit operation during said first time period only after said first energy stored level is reached, wherein the charging cost circuit pauses operation of said charging circuit whenever said charging cost rate is above the first threshold, and wherein the charging cost circuit turns on the charging circuit during said second time period in which the charging cost rate is above the first threshold and continues operation of said charging circuit until the battery reaches a second energy stored level or a user disrupts said charging circuit, wherein said second energy stored level is greater than said first energy stored level.