Thanks..... Great info....... I did read a post about the dc to dc charging, just haven't needed it yet. But it is definitely in the future project file...... The current system, which is the 400 watt system, works well. The batteries charge to 100% on sunny days, when I am away from the trailer. So no complaints. Although I do have a few 100 watt panels I can use if need be...,.... We were at a bluegrass festival. 5 days. The batteries cycled between 75% to 100%. I did run a generator while using the oven, but the panels did most of the work the rest of the time. I was being very conservative with my usage. Did not mind, worked great.,..... Again thanks for your help .....