Aux power from truck to fifth wheel
Cannot find any positive results from search for this question. How much voltage should be coming from the truck (when running) to the aux power "in" at the plug in? I have a 2007 JAYCO 36 RLTS and...
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When I got a new alternator for our 1992 GM van, the voltage increased considerably. It seems to me the "best" charging voltage has been increasing lately and alternator manufacturers have turned it up a notch. (Contrary to the otherwise excellent thread linked in a previous post, the voltage is controlled by changing the current flowing into the alternator electromagnets.) I wonder how vehicles with computer controlled alternator voltage decide what voltage to use? Ideally they would monitor current in and out of the battery to calculate the % of full charge and run 14.5 volts until 80 or 90 % charged - ending chronic undercharging for vehicles that mostly do short trips in a cold climate.
Before solar when we were dependent on engine charging (and after losing a pair of batteries to undercharging), I checked out the wire from engine to house on our motorhome and found a drop of half a volt across a joint. Fixing that made a significant increase in the charging current. Strangely, the charging current traveled an extra 20 feet each way to a battery cutoff switch at the door, which lost more than half a volt, mostly in the switch. The solution for that was to connect the engine charging wire directly to the battery.
The charging is through the Ford auxiliary battery charging system which includes a relay to connect only when the engine is running. I found no voltage drop in the relay but systems with a diode to prevent current from flowing backward from house battery to engine drop at least half a volt.
I ended up with house battery charging voltage half a volt below engine battery, up to 5 amps of engine charging, double what I had before. Certainly not enough to power a fridge in DC mode but it helped.
Before solar when we were dependent on engine charging (and after losing a pair of batteries to undercharging), I checked out the wire from engine to house on our motorhome and found a drop of half a volt across a joint. Fixing that made a significant increase in the charging current. Strangely, the charging current traveled an extra 20 feet each way to a battery cutoff switch at the door, which lost more than half a volt, mostly in the switch. The solution for that was to connect the engine charging wire directly to the battery.
The charging is through the Ford auxiliary battery charging system which includes a relay to connect only when the engine is running. I found no voltage drop in the relay but systems with a diode to prevent current from flowing backward from house battery to engine drop at least half a volt.
I ended up with house battery charging voltage half a volt below engine battery, up to 5 amps of engine charging, double what I had before. Certainly not enough to power a fridge in DC mode but it helped.
