[scrubjaysnest]

Originally Posted by rickst29

and not so much from running the Fridge from a bypass wire.

If we assume the total length of 10 AWG Fridge wire avoided (+12VDC) to be 15-20 feet, the the voltage drop along that length (at 11A) is about 0.26V. The power loss, for Fridge alone, is only about 3 Watts. The Key reason, however, why this mod (and its variations) makes such an enormous difference is the combined load.

11A for the Fridge, plus some and some amount of current which will ultimately leave the WFCO DC Distribution Panel on the battery circuit (charging batteries), are added together on the same wire for the portion from Bargeman back to the WFCO, (i.e., it's DC DIstribution panel). Suppose that battery charging load is, under your current "conditions", another 10A. If voltage really held up at 12.8V, into the WFCO, then there would be (roughly) .10 Voltage drop on the segment from WFCO to Fridge, and (roughly) .12 Voltage drop on the segment from WFCO to the Battery +12V inline fuse. But the segment from Bargeman to WFCO is loaded with 21 Amps, and (If I assume the +12V inside the cable to be another "skinny" 10 AWG, for length of about 15 feet) then the Voltage drop on that segment (alone) is about 0.5V, almost 4%.

5x as much Voltage drop getting to the WFCO with that wire carrying both loads - and, with so much less Voltage present at the WFCO panel on it's Battery and Fridge circuits, battery charging will be much slower. The fridge will also be a bit harder to keep cool.
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My summary: Messing around with a new wire to the Fridge doesn't save a lot of power, or create significantly better refrigeration. (The external on/off switch is probably nice to have.) The Key to Everything is getting the battery charge current onto a separate path of wire(s) from the Fridge current. As early as possible, and definitely before running all the way down the TM to reach the WFCO.

What was done is 8awg was run to the TM battery from the TV, breakers at both ends with the switch to feed DC to the refrig from the 8awg line only. TV charge line was upgraded to 10 awg from about 22 awg, TM already uses 10 awg to the battery. Both ends of the 10 awg have breakers. The DC feed from the WFCO to the refrig was deleted. My tests on the refrig showed a 1 amp draw/volt. ie 12 volts at the refrig, the current was 12 amps; 14 amps at 14 volts. Makes sense as the refrig heaters on AC or DC are nothing more then big resistors.