A cruising range display system, comprising:
- a battery unit including a battery that supplies a vehicle with electric power for driving;
- and
- a navigation device that is to be connected to the vehicle, wherein:
- the battery unit or the navigation device includes
- a storage unit that stores a lookup table which includes degradation coefficients each representing credibility of a full charging amount that decreases due to degradation of the battery;
- a degradation coefficient determination unit that determines a degradation coefficient among the degradation coefficients by using the lookup table stored in the storage unit;
- the battery unit includes
- a remaining amount calculation unit that calculates a remaining amount of the battery,
- a full charge amount calculation unit that calculates a full charge amount of the battery,
- an amount recording unit that records the full charge amount of the battery calculated by the full charge amount calculation unit, and
- a charging information transmission unit that transmits the remaining amount of the battery calculated by the remaining amount calculation unit and the full charge amount recorded by the amount recording unit as charging information to the navigation device;
- and
- the navigation device includes
- a current location calculation unit that calculates a current location of the vehicle,
- a vicinity map display unit that displays a vicinity map showing a vicinity of the current location of the vehicle on a display screen,
- a charging information reception unit that receives the charging information transmitted by the charging information transmission unit,
- a cruising range calculation unit that calculates a first cruising range of the vehicle based on the remaining amount and the full charge amount contained in the charging information received by the charging information reception unit,
- a second cruising range calculation unit that calculates a second cruising range, which is smaller than the first cruising range, based on the degradation coefficient and the first cruising range, and
- a cruising range display unit that displays a predetermined display representing the second cruising range on the vicinity map, wherein
- the cruising range display unit displays the first cruising range and the second cruising range along a road that extends from the current location of the vehicle on the vicinity map,
- the amount recording unit records the full charge amount calculated by the full charge amount calculation unit together with date and time of recording thereof;
- the charging information transmission unit transmits charging information containing the date and time of recording to the navigation device;
- the degradation coefficients included in the lookup table are determined according to elapsed time from the date and time of recording;
- and
- the degradation coefficient determination unit is included by the navigation device and determines the degradation coefficient by using the lookup table based on the date and time of recording and present date and time.