Mike,
I have used jumper cables a few times to do the same thing and it worked just fine. I only need to charge my batteries this way while dry camping 2 or 3 times a year so I decided not to deal with a separate generator. I like your connectors much better than my jumper cables though.
I have solar panels but when I camp in deep shaded sites, they don't do much good. DW and I are good at minimizing battery usage to about 30 AHs per day so we can go 2 or 3 days without charging.
For me, letting my gasoline truck idle for 60 to 90 minutes while it charges up my trailer batteries is a nice "emergency charging method". If I was going to be dry camping in shade for weeks on end, I would probably consider getting a quiet generator.
Last year, I built a "voltage booster" contraption from some $9 ebay components and used it successfully to keep my batteries charged during a 9 day camping trip in the Adirondacks with full shade. Details on the contraption here:
voltage booster contraption postEd
