So these are the voltages from truck.
Start up is 30 seconds. Stays at 14.4 for this time.
Here is after 30 seconds. Volts vary. Goes 14.6, 14.8, 15.10, etc etc.
Here is the camper charging off the truck.. This is my charge controller reading the voltage. Its the same at the batts with my test. About 2.3 amps going in from truck. No load. Just ran furnace to take off surface charge.
After running furnace to take off surface charge for a few minutes. Bot batts voltage taken.
Both batts 13.26.
I need to fine better leads ( longer) to do the voltage drop test across wiring.
Truck batterys voltages are different. I assume the starting battery has some type of draw on it. I do leave a usb charger in the cig lighter aux port 24/7.
Truck batt 12.5 in am, aux batt 13.xx
