A multiple battery system includes a battery housing, first and second batteries disposed in the battery housing, a one-way charging circuit, and at least one switching device. The battery housing includes at least one positive terminal and at least one negative terminal, which are electrically coupleable to an electrical system. Each battery includes respective positive and negative outputs. The negative output of each battery is electrically connected to the negative terminal(s) of the battery housing. The one-way charging circuit is electrically connected between the positive outputs of the two batteries and is configured to facilitate charging of, but prevent current flow from, the second battery when the first battery is supplying electrical energy to the electrical system. The switching device(s) is operable in at least two states to selectively electrically connect the positive terminal(s) of the battery housing to a selective one of the positive outputs of the two batteries.