arge my tow campers batteries with my car battery until solar is hooked up
If you are asking if your tow vehicle can charge the batteries on your trailer, it can if your wiring is set up to do that. Charging with the vehicle is not an efficient way to charge and will take time.
If you have a 7 wire hook-up from the tow vehicle it will charge your battery as you drive. However, if you have a refrigerator that is on it will still take down the charge from the battery. I have a 100 watt lithium battery and even if it starts off fully charged on a long drive the battery will be down to 60+% when I stop.
Two points of clarification on Judy_B’s reply:
The battery will be charged if you have a 7 pin connector AND the pin for charging is connected properly so that it provides power. Always double check that.
The battery will be drained if the refrigerator is running on 12 volt. If it is running on propane, there will be little or no effect on battery.
Points taken. I know there are a variety of opinions on towing with propane on. I personally don’t do that. I did find that if the refrigerator is cooled down for at least 24 hours prior to leaving and then turned off from all power, it will remain cool. Then when I stop to camp, I can boot up the propane and all is good, cold frig (beer) and full battery.