A method comprising: monitoring at least one energy source characteristic of at least one of a plurality of finite energy sources, wherein the plurality of finite energy sources comprises a plurality of battery modules and wherein said monitoring at least one energy source characteristic comprises calculating a quantity of energy expended from a first battery module; monitoring at least one load characteristic of a present load, the monitoring at least one load characteristic comprising determining whether the present load is a low-power load or a high-power load; selecting one of the plurality of finite energy sources in response to the monitoring at least one energy source characteristic and the monitoring at least one load characteristic; and scheduling the present load to the selected finite energy source, wherein the selecting one of the plurality of finite energy sources comprises: selecting according to a first selection mode when the quantity of energy expended from the first battery module is less than or equal to a switching threshold, the first selection mode comprising selecting the first battery module; and selecting according to a second selection mode when the quantity of energy expended from the first battery module is greater than the switching threshold, the second selection mode comprising: scheduling low-power loads to the first battery module; and scheduling high-power loads to a second battery module. monitoring at least one energy source characteristic of at least one of a plurality of finite energy sources, wherein the plurality of finite energy sources comprises a plurality of battery modules and wherein said monitoring at least one energy source characteristic comprises calculating a quantity of energy expended from a first battery module; monitoring at least one load characteristic of a present load, the monitoring at least one load characteristic comprising determining whether the present load is a low-power load or a high-power load; selecting one of the plurality of finite energy sources in response to the monitoring at least one energy source characteristic and the monitoring at least one load characteristic; and scheduling the present load to the selected finite energy source, wherein the selecting one of the plurality of finite energy sources comprises: selecting according to a first selection mode when the quantity of energy expended from the first battery module is less than or equal to a switching threshold, the first selection mode comprising selecting the first battery module; and selecting according to a second selection mode when the quantity of energy expended from the first battery module is greater than the switching threshold, the second selection mode comprising: scheduling low-power loads to the first battery module; and scheduling high-power loads to a second battery module. selecting according to a first selection mode when the quantity of energy expended from the first battery module is less than or equal to a switching threshold, the first selection mode comprising selecting the first battery module; and selecting according to a second selection mode when the quantity of energy expended from the first battery module is greater than the switching threshold, the second selection mode comprising: scheduling low-power loads to the first battery module; and scheduling high-power loads to a second battery module. scheduling low-power loads to the first battery module; and scheduling high-power loads to a second battery module.