Trunk Battery

[Daixiwen]

The 12V battery is not used to start the engine so you don't need a high cranking power. What it mostly needs to do is to provide enough power to the main contactor to connect the high voltage to the rest of the system and each relay coil uses less than one amp (DC resistance is in the 20 ohm region). So as long as the 12V battery can provide a couple of amps you are good.