In-vehicle charging system

An in-vehicle charging system that charges a battery mounted on an electric vehicle with electric power supplied from a home, the in-vehicle charging system comprising:

• an external environment recognition unit that is mounted on the electric vehicle and detects external environment information regarding an external environment around the electric vehicle;
• an information acquiring unit that acquires device information regarding an electric device provided in the home;
• a power consumption estimating unit that calculates a power consumption estimation value of the electric device provided in the home upon charging the battery on the basis of the external environment information and the device information;
• and
• a charging power determination unit that determines a charging plan for the battery based on the power consumption estimation value, wherein
• the charging power determination unit determines the charging plan in such a manner that a sum of charging power of the battery and the power consumption estimation value falls below an upper limit value of electric power consumable in the home.