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In normal cars, there is a 12V lead-acid battery that is used as a to start the engine and power general electronics within the car. The same concept is shared in a solar car, where we have a supplementary battery that is used to start the car and switch over to the main battery pack. There are a number of high-voltage relays that control power to the battery pack, motors, and solar array. These relays are used to ensure that systems are connected in the correct order and that all high-voltage systems are disconnected in the case of a battery fault. In general, all solar cars have a LV power rail that operates around 12V and a HV power rail that operates at the main battery pack voltage.
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