A method of charging a battery in a system involving a renewable energy source and operable to supply at least some electrical energy from the renewable energy source to a third party involves causing a charge controller operably connected to the renewable energy source to receive the electrical energy from the renewable energy source and operably connected to the battery, to charge the battery, using only the electrical energy from the renewable energy source, according to a charging sequence. The charging sequence includes at least a bulk charge period wherein the battery is charged at a relatively constant charging current, an absorption period following the bulk charge period wherein the battery is charged in an absorption mode, and a float period following the absorption period wherein the battery is charged in a float charging mode.