Thx all. Like I said we've gone this long with solar only with no issues in the past. We're not using alot of power, and the solar more than covers refrigerator and water pump, radio, etc. even in sketchy condition. Generator is not an option, absolutely hate them for camping, won't own one, and we have no pressing need for microwave, AC, or hairdryer :R. Wife and girls will survive just fine without them for a few days.
Question was more about how to best use spare 12volts in a pinch. Sounds like best option is to simply swap out if the time comes.
We're heading out on an extended trip of about 10 days, battery power only. No plug-ins, although I do have 2 T-105's and 230 watt solar to keep us going. We've never had an issue keeping charged even in trees or bad weather, and I have a couple extra 12volt batteries I'll pack if I think we may need them.
I've never actually needed to use the extra 12volt batt's, question is what is the best way to hook them up to the camper system if I do happen to need them? Jumper cables? Remove the old discharged batts and replace with the charged batts? Thoughts?