Stand alone starting battery for generator

I just got done dry camping for a week and had some issues with this as well. Found loose connections on a couple battery posts :S but after running the generator for a few hours still no charge. Poked around with my meter and found the converter was not charging the batteries. Since we were leaving the next day just hooked up my battery charger and got enough juice to get me by. When I got home I found that the converter output wires were loose, now all is good.

Did the same thing with the truck, plugged it in and ran for about 10 minutes and started genny. I don't see a need for a dedicated battery since its not that hard to do the above.