Well, hereís Steve L.'s new "test" box.
It's designed to go between the tow and the trailer.
Most of the LEDs are self explanatory. The Trailer Charge LED lights
if there is power going to the trailer battery
. On the Ford, turn off the ignition key and the light
goes out and the trailer is running off its own battery
and not draining the tow vehicle's battery
. I fabricated a 6 foot cable with two male ends for the tow to test box connection. It stores more easily if you can disconnect the cable.
The first picture shows it in Voltage setting. I tried to catch the turn signal LEDs when they were on (4 way flasher) but I couldn't time the shutter properly. They're red. Hard to see but the tow is putting out about 13.4 volts at idle.
The second picture shows it in Amperage mode with the reefer on 12v. I know the reefer is pulling about 10amp but this picture is showing only about 5 amps are being supplied by the tow while it's idling. The rest is being supplied by the trailer battery. I expect at the 1500 to 2000 rpm I cruise at this number would go up. One of these days I'll ask somebody to look at the meter while I hold the revs up some to see where I am.
At idle, all loads off, the tow is trickling about 1 amp to the trailer battery.
I remain convinced that the tow vehicle will not return a battery to full charge. Mostly based on my past studies with the Link 10. I will try it again when I'm dry camping
. This is redundant to the Link 10 but I can take it to someone else's trailer to show them as well.
I have some LCD panel meters coming for me to play with. Version 2 will have two LCD meters permanently set on the face so that I don't have to carry the separate ammeter.