NOVELTY - A system comprises a saturated electrolyte unit (1-10) having at least one inlet (1-90) and at least one outlet; and a diluted electrolyte unit (1-20) containing inlet and outlet. The system further comprises at least one heat exchanger (1-60b) connected to the saturated electrolyte unit or to the diluted electrolyte unit. In the system, a first inlet of the saturated electrolyte unit, and/or a second inlet of the diluted electrolyte unit are connected to a liquid source (1-30) from which liquid can be transferred to the saturated electrolyte unit, and/or to the diluted electrolyte unit.    USE - As a system for producing an electrolyte which is used in a metal air battery (i.e. an aluminum air battery) for operating an electric vehicle including bicycle, car, truck, bus, motorcycle, train, ship, boat, aircraft or spacecraft (claimed).    ADVANTAGE - The system efficiently and safely replenishes liquid electrolyte in a battery on e.g. an electrically-operated vehicle; provides simpler and less expensive infrastructure for supplies as only solid is transported, and is diluted on-board; and provides increased safety and heat management efficiency due to dilution in two steps. The system has the advantage that after system initialization the user only needs to add more water to produce more electrolyte.    DETAILED DESCRIPTION - A system comprises a saturated electrolyte unit (1-10) having at least one inlet (1-90) and at least one outlet; and a diluted electrolyte unit (1-20) containing at least one inlet and at least one outlet, where a first outlet of the saturated electrolyte unit is connected to a first inlet of the diluted electrolyte unit such that saturated electrolyte can be transferred from the saturated electrolyte unit to the diluted electrolyte unit, and where the first outlet of the diluted electrolyte unit is connected to the metal air battery. The system further comprises at least one heat exchanger (1-60b) connected to the saturated electrolyte unit or to the diluted electrolyte unit. In the system, a first inlet of the saturated electrolyte unit, and/or a second inlet of the diluted electrolyte unit are connected to a liquid source (1-30) from which liquid can be transferred to the saturated electrolyte unit, and/or to the diluted electrolyte unit. INDEPENDENT CLAIMS are included for the following:    (1) an electric vehicle comprising the system, where the vehicle drives on metal air energy and where water is transferred to the saturated electrolyte unit, and/or to diluted electrolyte unit for electrolyte generation to allow additional driving range;    (2) producing electrolyte for a metal air battery, involving preparing a saturated electrolyte solution from a solid ionic compound and from a liquid in a saturated electrolyte unit such that the unit comprises both solution and solid, transferring a portion of saturated electrolyte solution from saturated electrolyte unit to a diluted electrolyte unit, and adding water to diluted electrolyte unit, where the water mix with saturated solution within diluted electrolyte unit to form a diluted electrolyte composition at a concentration suitable for a metal air battery.    DESCRIPTION OF DRAWING(S) - The figure shows a flow chart illustrating an electrolyte production system and method of preparing the electrolyte.    Saturated electrolyte unit (1-10)    Diluted electrolyte unit (1-20)    Liquid source (1-30)    Heat exchanger (1-60b)    Inlet (1-90)