The "class K" 8 awg copper welding wire (161 strands of 30awg) I used to rewire my jack controller inside the TC has a resistance (R) of 0.000772 ohms per foot.
Doesn't seem like much, but when you include the overall length (L) of the circuit (positive + negative cable lengths), a voltage drop (Vd) will occur depending on the current (I) in amps.
Vd = R x L x I
Voltage (V) at my truck alternator is usually around 14.4
Voltage at bed plug (Vbp) = V - Vd
Whether this is an issue or not depends on your use. Running a "12" VDC device is usually not an issue (typical input VDC tolerance is 10.5 to 15.4) just check your device manual.
Just the voltage drop to the bed plug results in Vtc = 14.2 @ 10A; 14.0 @ 20A; 13.8 @ 30A. The final voltage drop at the batteries will be even greater, depending on the wire gauge and the length used from there to inside the TC to the batteries or device.
As the voltage drop causes the voltage at the batteries to approach the "Float" voltage, very little charging is occurring. For charging 220 Ah and larger AGM battery banks, short lengths of larger diameter wire are used to recharge the batteries in a reasonable time, while driving.
You might ask Buzzcut1 what he typically has experienced after the 3 hr drive from the Sierra, as he has the 8 awg Lance Bed Plug.
