example of daisey-chained wiring... using 10g for main feed, 16g to dc-dc, 12g to heater, and 16 around to state-of-charge voltmeter. I used a separate feed for the 'raw' voltmeter from the keyed side of the contactor so that the gauge would give visible feedback when contactor closes. SOC 'fuel' gauge needs to be on all the time for best results.